Hi Kyrill,

Please find an updated version in attachment. Please note I made quite a few 
other changes as well. The most important one was to add new ARMv8-M Baseline 
only alternatives to the two movt insns in order to have non predicable output 
template for ARMv8-M Baseline. I also inverted the logic for how to detect 
ARMv8-M Baseline in the testsuite (arm_thumb1_movt_ok rather than *_ko) and 
fixed a couple of typos. I didn't add MOVT test because it is difficult to 
generate. Using -mslow-flash-data should help but it is not available for 
ARMv8-M Baseline as only config/arm/thumb2.md was modified to support this 
option.

Update ChangeLog entries are as follow:


*** gcc/ChangeLog ***

2016-06-20  Thomas Preud'homme  <thomas.preudho...@arm.com>

        * config/arm/arm.h (TARGET_HAVE_MOVT): Include ARMv8-M as having MOVT.
        * config/arm/arm.c (arm_arch_name): (const_ok_for_op): Check MOVT/MOVW
        availability with TARGET_HAVE_MOVT.
        (thumb_legitimate_constant_p): Strip the high part of a label_ref.
        (thumb1_rtx_costs): Also return 0 if setting a half word constant and
        MOVW is available and replace (unsigned HOST_WIDE_INT) INTVAL by
        UINTVAL.
        (thumb1_size_rtx_costs): Make set of half word constant also cost 1
        extra instruction if MOVW is available.  Use a cost variable
        incremented by COSTS_N_INSNS (1) when the condition match rather than
        returning an arithmetic expression based on COSTS_N_INSNS.  Make
        constant with bottom half word zero cost 2 instruction if MOVW is
        available.
        * config/arm/arm.md (define_attr "arch"): Add v8mb.
        (define_attr "arch_enabled"): Set to yes if arch value is v8mb and
        target is ARMv8-M Baseline.
        (arm_movt): New unpredicable alternative for ARMv8-M Baseline.
        (arm_movtas_ze): Likewise.
        * config/arm/thumb1.md (thumb1_movdi_insn): Add ARMv8-M Baseline only
        alternative for constants satisfying j constraint.
        (thumb1_movsi_insn): Likewise.
        (movsi splitter for K alternative): Tighten condition to not trigger
        if movt is available and j constraint is satisfied.
        (Pe immediate splitter): Likewise.
        (thumb1_movhi_insn): Add ARMv8-M Baseline only alternative for
        constant fitting in an halfword to use MOVW.
        * doc/sourcebuild.texi (arm_thumb1_movt_ok): Document new ARM
        effective target.


*** gcc/testsuite/ChangeLog ***

2016-05-23  Thomas Preud'homme  <thomas.preudho...@arm.com>

        * lib/target-supports.exp (check_effective_target_arm_thumb1_movt_ok):
        Define effective target.
        * gcc.target/arm/pr42574.c: Require arm_thumb1_ok and
        !arm_thumb1_movt_ok to exclude ARMv8-M Baseline.
        * gcc.target/arm/movhi_movw.c: New test.
        * gcc.target/arm/movsi_movw.c: Likewise.
        * gcc.target/arm/movdi_movw.c: Likewise.


Best regards,

Thomas

On Friday 20 May 2016 12:14:44 Kyrill Tkachov wrote:
> Hi Thomas,
> 
> On 19/05/16 17:11, Thomas Preudhomme wrote:
> > On Wednesday 18 May 2016 12:30:41 Kyrill Tkachov wrote:
> >> Hi Thomas,
> >> 
> >> This looks mostly good with a few nits inline.
> >> Please repost with the comments addressed.
> > 
> > Updated ChangeLog entries:
> > 
> > *** gcc/ChangeLog ***
> > 
> > 2016-05-18  Thomas Preud'homme  <thomas.preudho...@arm.com>
> > 
> >          * config/arm/arm.h (TARGET_HAVE_MOVT): Include ARMv8-M as having
> >          MOVT.
> >          * config/arm/arm.c (arm_arch_name): (const_ok_for_op): Check
> >          MOVT/MOVW
> >          availability with TARGET_HAVE_MOVT.
> >          (thumb_legitimate_constant_p): Strip the high part of a
> >          label_ref.
> >          (thumb1_rtx_costs): Also return 0 if setting a half word constant
> >          and
> >          MOVW is available and replace (unsigned HOST_WIDE_INT) INTVAL by
> >          UINTVAL.
> >          (thumb1_size_rtx_costs): Make set of half word constant also cost
> >          1
> >          extra instruction if MOVW is available.  Use a cost variable
> >          incremented by COSTS_N_INSNS (1) when the condition match rather
> >          than
> >          returning an arithmetic expression based on COSTS_N_INSNS.  Make
> >          constant with bottom half word zero cost 2 instruction if MOVW is
> >          available.
> >          * config/arm/arm.md (define_attr "arch"): Add v8mb.
> >          (define_attr "arch_enabled"): Set to yes if arch value is v8mb
> >          and
> >          target is ARMv8-M Baseline.
> >          * config/arm/thumb1.md (thumb1_movdi_insn): Add ARMv8-M Baseline
> >          only
> >          alternative for constants satisfying j constraint.
> >          (thumb1_movsi_insn): Likewise.
> >          (movsi splitter for K alternative): Tighten condition to not
> >          trigger
> >          if movt is available and j constraint is satisfied.
> >          (Pe immediate splitter): Likewise.
> >          (thumb1_movhi_insn): Add ARMv8-M Baseline only alternative for
> >          constant fitting in an halfword to use MOVW.
> >          * doc/sourcebuild.texi (arm_thumb1_movt_ko): Document new ARM
> >          effective target.
> > 
> > *** gcc/testsuite/ChangeLog ***
> > 
> > 2015-11-13  Thomas Preud'homme  <thomas.preudho...@arm.com>
> > 
> >          * lib/target-supports.exp
> >          (check_effective_target_arm_thumb1_movt_ko):
> >          Define effective target.
> >          * gcc.target/arm/pr42574.c: Require arm_thumb1_movt_ko instead of
> >          arm_thumb1_ok as effective target to exclude ARMv8-M Baseline.
> 
> This is ok now, thanks for the changes.
> I'd like to see some tests that generate MOVW/MOVT instructions
> on ARMv8-M Baseline. They should be easy, just an:
> int
> foo ()
> {
>    return CONST;
> }
> 
> and same for short and long long return types
> (to exercise the HI, SI and DImode move patterns).
> 
> You can add them as part of this patch or as a separate followup.
> 
> Thanks,
> Kyrill
> 
> > and patch:
> > 
> > diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
> > index
> > 47216b4a1959ccdb18e329db411bf7f941e67163..f42e996e5a7ce979fe406b8261d50fb2
> > ba005f6b 100644
> > --- a/gcc/config/arm/arm.h
> > +++ b/gcc/config/arm/arm.h
> > @@ -269,7 +269,7 @@ extern void (*arm_lang_output_object_attributes_hook)
> > (void);
> > 
> >   #define TARGET_HAVE_LDACQ (TARGET_ARM_ARCH >= 8 && arm_arch_notm)
> >   
> >   /* Nonzero if this chip provides the movw and movt instructions.  */
> > 
> > -#define TARGET_HAVE_MOVT   (arm_arch_thumb2)
> > +#define TARGET_HAVE_MOVT   (arm_arch_thumb2 || arm_arch8)
> > 
> >   /* Nonzero if integer division instructions supported.  */
> >   #define TARGET_IDIV       ((TARGET_ARM && arm_arch_arm_hwdiv)     \
> > 
> > diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> > index
> > d75a34f10d5ed22cff0a0b5d3ad433f111b059ee..a05e559c905daa55e686491a03834236
> > 0c721912 100644
> > --- a/gcc/config/arm/arm.c
> > +++ b/gcc/config/arm/arm.c
> > @@ -8220,6 +8220,12 @@ arm_legitimate_constant_p_1 (machine_mode, rtx x)
> > 
> >   static bool
> >   thumb_legitimate_constant_p (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
> >   {
> > 
> > +  /* Splitters for TARGET_USE_MOVT call arm_emit_movpair which creates
> > high +     RTX.  These RTX must therefore be allowed for Thumb-1 so that
> > when run +     for ARMv8-M baseline or later the result is valid.  */
> > +  if (TARGET_HAVE_MOVT && GET_CODE (x) == HIGH)
> > +    x = XEXP (x, 0);
> > +
> > 
> >     return (CONST_INT_P (x)
> >     
> >       || CONST_DOUBLE_P (x)
> >       || CONSTANT_ADDRESS_P (x)
> > 
> > @@ -8306,7 +8312,8 @@ thumb1_rtx_costs (rtx x, enum rtx_code code, enum
> > rtx_code outer)
> > 
> >       case CONST_INT:
> >         if (outer == SET)
> >     
> >     {
> > 
> > -     if ((unsigned HOST_WIDE_INT) INTVAL (x) < 256)
> > +     if (UINTVAL (x) < 256
> > +         || (TARGET_HAVE_MOVT && !(INTVAL (x) & 0xffff0000)))
> > 
> >         return 0;
> >       
> >       if (thumb_shiftable_const (INTVAL (x)))
> >       
> >         return COSTS_N_INSNS (2);
> > 
> > @@ -9009,7 +9016,7 @@ static inline int
> > 
> >   thumb1_size_rtx_costs (rtx x, enum rtx_code code, enum rtx_code outer)
> >   {
> >   
> >     machine_mode mode = GET_MODE (x);
> > 
> > -  int words;
> > +  int words, cost;
> > 
> >     switch (code)
> >     
> >       {
> > 
> > @@ -9055,17 +9062,26 @@ thumb1_size_rtx_costs (rtx x, enum rtx_code code,
> > enum rtx_code outer)
> > 
> >         /* A SET doesn't have a mode, so let's look at the SET_DEST to get
> >      
> >      the mode.  */
> >      
> >         words = ARM_NUM_INTS (GET_MODE_SIZE (GET_MODE (SET_DEST (x))));
> > 
> > -      return COSTS_N_INSNS (words)
> > -        + COSTS_N_INSNS (1) * (satisfies_constraint_J (SET_SRC (x))
> > -                               || satisfies_constraint_K (SET_SRC (x))
> > -                                  /* thumb1_movdi_insn.  */
> > -                               || ((words > 1) && MEM_P (SET_SRC (x))));
> > +      cost = COSTS_N_INSNS (words);
> > +      if (satisfies_constraint_J (SET_SRC (x))
> > +     || satisfies_constraint_K (SET_SRC (x))
> > +        /* Too big immediate for 2byte mov, using movt.  */
> > +     || (UINTVAL (SET_SRC (x)) >= 256
> > +         && TARGET_HAVE_MOVT
> > +         && satisfies_constraint_j (SET_SRC (x)))
> > +        /* thumb1_movdi_insn.  */
> > +     || ((words > 1) && MEM_P (SET_SRC (x))))
> > +   cost += COSTS_N_INSNS (1);
> > +      return cost;
> > 
> >       case CONST_INT:
> >         if (outer == SET)
> >         
> >           {
> >           
> >             if ((unsigned HOST_WIDE_INT) INTVAL (x) < 256)
> >             
> >               return COSTS_N_INSNS (1);
> > 
> > +     /* movw is 4byte long.  */
> > +     if (TARGET_HAVE_MOVT && !(INTVAL (x) & 0xffff0000))
> > +       return COSTS_N_INSNS (2);
> > 
> >       /* See split "TARGET_THUMB1 && satisfies_constraint_J".  */
> >       if (INTVAL (x) >= -255 && INTVAL (x) <= -1)
> >       
> >               return COSTS_N_INSNS (2);
> > 
> > diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
> > index
> > 8aa9fedf5c07e78bc7ba793b39bebcc45a4d5921..ce39bdf5904dec3e12003c411f2a8b32
> > 6ea939e3 100644
> > --- a/gcc/config/arm/arm.md
> > +++ b/gcc/config/arm/arm.md
> > @@ -118,10 +118,10 @@
> > 
> >   ; This can be "a" for ARM, "t" for either of the Thumbs, "32" for
> >   ; TARGET_32BIT, "t1" or "t2" to specify a specific Thumb mode.  "v6"
> >   ; for ARM or Thumb-2 with arm_arch6, and nov6 for ARM without
> > 
> > -; arm_arch6.  "v6t2" for Thumb-2 with arm_arch6.  This attribute is
> > -; used to compute attribute "enabled", use type "any" to enable an
> > -; alternative in all cases.
> > -(define_attr "arch"
> > "any,a,t,32,t1,t2,v6,nov6,v6t2,neon_for_64bits,avoid_neon_for_64bits,iwmmx
> > t,iwmmxt2,armv6_or_vfpv3,neon" +; arm_arch6.  "v6t2" for Thumb-2 with
> > arm_arch6 and v8mb for ARMv8-M +; baseline.  This attribute is used to
> > compute attribute "enabled", +; use type "any" to enable an alternative
> > in all cases.
> > +(define_attr "arch"
> > "any,a,t,32,t1,t2,v6,nov6,v6t2,v8mb,neon_for_64bits,avoid_neon_for_64bits,
> > iwmmxt,iwmmxt2,armv6_or_vfpv3,neon"> 
> >     (const_string "any"))
> >   
> >   (define_attr "arch_enabled" "no,yes"
> > 
> > @@ -160,6 +160,10 @@
> > 
> >           (match_test "TARGET_32BIT && arm_arch6 && arm_arch_thumb2"))
> >      
> >      (const_string "yes")
> > 
> > +    (and (eq_attr "arch" "v8mb")
> > +         (match_test "TARGET_THUMB1 && arm_arch8"))
> > +    (const_string "yes")
> > +
> > 
> >      (and (eq_attr "arch" "avoid_neon_for_64bits")
> >      
> >           (match_test "TARGET_NEON")
> >           (not (match_test "TARGET_PREFER_NEON_64BITS")))
> > 
> > diff --git a/gcc/config/arm/thumb1.md b/gcc/config/arm/thumb1.md
> > index
> > 072ed4da47ad164eb406bedc3fccc589ac705e9f..47e569d0c259cd17d86a03061e5b47b3
> > dab4579f 100644
> > --- a/gcc/config/arm/thumb1.md
> > +++ b/gcc/config/arm/thumb1.md
> > @@ -590,8 +590,8 @@
> > 
> >   ;;; ??? The 'i' constraint looks funny, but it should always be replaced
> >   by
> >   ;;; thumb_reorg with a memory reference.
> >   (define_insn "*thumb1_movdi_insn"
> > 
> > -  [(set (match_operand:DI 0 "nonimmediate_operand" "=l,l,l,l,>,l, m,*r")
> > -   (match_operand:DI 1 "general_operand"      "l, I,J,>,l,mi,l,*r"))]
> > +  [(set (match_operand:DI 0 "nonimmediate_operand" "=l,l,l,r,l,>,l,
> > m,*r")
> > +   (match_operand:DI 1 "general_operand"      "l, I,J,j,>,l,mi,l,*r"))]
> > 
> >     "TARGET_THUMB1
> >     
> >      && (   register_operand (operands[0], DImode)
> >      
> >          || register_operand (operands[1], DImode))"
> > 
> > @@ -609,37 +609,41 @@
> > 
> >       case 2:
> >         operands[1] = GEN_INT (- INTVAL (operands[1]));
> >         return \"movs\\t%Q0, %1\;rsbs\\t%Q0, %Q0, #0\;asrs\\t%R0, %Q0,
> >         #31\";
> > 
> > -    case 3:
> > -      return \"ldmia\\t%1, {%0, %H0}\";
> > +    case 3: gcc_assert (TARGET_HAVE_MOVT);
> > +       return \"movw\\t%Q0, %L1\;movs\\tR0, #0\";
> > 
> >       case 4:
> > -      return \"stmia\\t%0, {%1, %H1}\";
> > +      return \"ldmia\\t%1, {%0, %H0}\";
> > 
> >       case 5:
> > -      return thumb_load_double_from_address (operands);
> > +      return \"stmia\\t%0, {%1, %H1}\";
> > 
> >       case 6:
> > +      return thumb_load_double_from_address (operands);
> > 
> > +    case 7:
> >         operands[2] = gen_rtx_MEM (SImode,
> >         
> >                          plus_constant (Pmode, XEXP (operands[0], 0), 4));
> >         
> >         output_asm_insn (\"str\\t%1, %0\;str\\t%H1, %2\", operands);
> >         return \"\";
> > 
> > -    case 7:
> > 
> > +    case 8:
> >         if (REGNO (operands[1]) == REGNO (operands[0]) + 1)
> >     
> >     return \"mov\\t%0, %1\;mov\\t%H0, %H1\";
> >     
> >         return \"mov\\t%H0, %H1\;mov\\t%0, %1\";
> >       
> >       }
> >     
> >     }"
> > 
> > -  [(set_attr "length" "4,4,6,2,2,6,4,4")
> > -   (set_attr "type"
> > "multiple,multiple,multiple,load2,store2,load2,store2,multiple")
> > -   (set_attr "pool_range" "*,*,*,*,*,1018,*,*")]
> > +  [(set_attr "length" "4,4,6,6,2,2,6,4,4")
> > +   (set_attr "type"
> > "multiple,multiple,multiple,multiple,load2,store2,load2,store2,multiple")
> > +   (set_attr "arch" "t1,t1,t1,v8mb,t1,t1,t1,t1,t1")
> > +   (set_attr "pool_range" "*,*,*,*,*,*,1018,*,*")]
> > 
> >   )
> >   
> >   (define_insn "*thumb1_movsi_insn"
> > 
> > -  [(set (match_operand:SI 0 "nonimmediate_operand" "=l,l,l,l,l,>,l,
> > m,*l*h*k")
> > -   (match_operand:SI 1 "general_operand"      "l, 
I,J,K,>,l,mi,l,*l*h*k"))]
> > +  [(set (match_operand:SI 0 "nonimmediate_operand" "=l,l,r,l,l,l,>,l,
> > m,*l*h*k")
> > +   (match_operand:SI 1 "general_operand"      "l,
> > I,j,J,K,>,l,mi,l,*l*h*k"))]
> > 
> >     "TARGET_THUMB1
> >     
> >      && (   register_operand (operands[0], SImode)
> >      
> >          || register_operand (operands[1], SImode))"
> >     
> >     "@
> >     
> >      movs   %0, %1
> >      movs   %0, %1
> > 
> > +   movw    %0, %1
> > 
> >      #
> >      #
> >      ldmia\\t%1, {%0}
> > 
> > @@ -647,10 +651,11 @@
> > 
> >      ldr\\t%0, %1
> >      str\\t%1, %0
> >      mov\\t%0, %1"
> > 
> > -  [(set_attr "length" "2,2,4,4,2,2,2,2,2")
> > -   (set_attr "type"
> > "mov_reg,mov_imm,multiple,multiple,load1,store1,load1,store1,mov_reg")
> > -   (set_attr "pool_range" "*,*,*,*,*,*,1018,*,*")
> > -   (set_attr "conds" "set,clob,*,*,nocond,nocond,nocond,nocond,nocond")])
> > +  [(set_attr "length" "2,2,4,4,4,2,2,2,2,2")
> > +   (set_attr "type"
> > "mov_reg,mov_imm,mov_imm,multiple,multiple,load1,store1,load1,store1,mov_r
> > eg") +   (set_attr "pool_range" "*,*,*,*,*,*,*,1018,*,*")
> > +   (set_attr "arch" "t1,t1,v8mb,t1,t1,t1,t1,t1,t1,t1")
> > +   (set_attr "conds"
> > "set,clob,nocond,*,*,nocond,nocond,nocond,nocond,nocond")])
> > 
> >   ; Split the load of 64-bit constant into two loads for high and low
> >   32-bit
> > 
> > parts respectively
> > 
> >   ; to see if we can load them in fewer instructions or fewer cycles.
> > 
> > @@ -687,7 +692,8 @@
> > 
> >   (define_split
> >   
> >     [(set (match_operand:SI 0 "register_operand" "")
> >     
> >     (match_operand:SI 1 "const_int_operand" ""))]
> > 
> > -  "TARGET_THUMB1 && satisfies_constraint_K (operands[1])"
> > +  "TARGET_THUMB1 && satisfies_constraint_K (operands[1])
> > +   && !(TARGET_HAVE_MOVT && satisfies_constraint_j (operands[1]))"
> > 
> >     [(set (match_dup 2) (match_dup 1))
> >     
> >      (set (match_dup 0) (ashift:SI (match_dup 2) (match_dup 3)))]
> >     
> >     "
> > 
> > @@ -714,7 +720,8 @@
> > 
> >   (define_split
> >   
> >     [(set (match_operand:SI 0 "register_operand" "")
> >     
> >     (match_operand:SI 1 "const_int_operand" ""))]
> > 
> > -  "TARGET_THUMB1 && satisfies_constraint_Pe (operands[1])"
> > +  "TARGET_THUMB1 && satisfies_constraint_Pe (operands[1])
> > +   && !(TARGET_HAVE_MOVT && satisfies_constraint_j (operands[1]))"
> > 
> >     [(set (match_dup 2) (match_dup 1))
> >     
> >      (set (match_dup 0) (plus:SI (match_dup 2) (match_dup 3)))]
> >     
> >     "
> > 
> > @@ -726,8 +733,8 @@
> > 
> >   )
> >   
> >   (define_insn "*thumb1_movhi_insn"
> > 
> > -  [(set (match_operand:HI 0 "nonimmediate_operand" "=l,l,m,l*r,*h,l")
> > -   (match_operand:HI 1 "general_operand"       "l,m,l,k*h,*r,I"))]
> > +  [(set (match_operand:HI 0 "nonimmediate_operand" "=l,l,m,l*r,*h,l,r")
> > +   (match_operand:HI 1 "general_operand"       "l,m,l,k*h,*r,I,n"))]
> > 
> >     "TARGET_THUMB1
> >     
> >      && (   register_operand (operands[0], HImode)
> >      
> >          || register_operand (operands[1], HImode))"
> > 
> > @@ -739,6 +746,8 @@
> > 
> >       case 3: return \"mov  %0, %1\";
> >       case 4: return \"mov  %0, %1\";
> >       case 5: return \"movs %0, %1\";
> > 
> > +    case 6: gcc_assert (TARGET_HAVE_MOVT);
> > +       return \"movw       %0, %L1\";
> > 
> >       default: gcc_unreachable ();
> >       
> >       case 1:
> >         /* The stack pointer can end up being taken as an index register.
> > 
> > @@ -758,9 +767,10 @@
> > 
> >     }
> >     
> >         return \"ldrh       %0, %1\";
> >       
> >       }"
> > 
> > -  [(set_attr "length" "2,4,2,2,2,2")
> > -   (set_attr "type" "alus_imm,load1,store1,mov_reg,mov_reg,mov_imm")
> > -   (set_attr "conds" "clob,nocond,nocond,nocond,nocond,clob")])
> > +  [(set_attr "length" "2,4,2,2,2,2,4")
> > +   (set_attr "type"
> > "alus_imm,load1,store1,mov_reg,mov_reg,mov_imm,mov_imm") +   (set_attr
> > "arch" "t1,t1,t1,t1,t1,t1,v8mb")
> > +   (set_attr "conds" "clob,nocond,nocond,nocond,nocond,clob,nocond")])
> > 
> >   (define_expand "thumb_movhi_clobber"
> >   
> >     [(set (match_operand:HI     0 "memory_operand"   "")
> > 
> > diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi
> > index
> > 3142cd53ae53e90bb1af2f595fe53778c1cbfd3b..860b4c0627e094bae8b3801f9256ff4f
> > ec5c8fc2 100644
> > --- a/gcc/doc/sourcebuild.texi
> > +++ b/gcc/doc/sourcebuild.texi
> > @@ -1601,6 +1601,10 @@ arm_v8_1a_neon_ok.
> > 
> >   ARM target prefers @code{LDRD} and @code{STRD} instructions over
> >   @code{LDM} and @code{STM} instructions.
> > 
> > +@item arm_thumb1_movt_ko
> > +ARM target generates Thumb-1 code for @code{-mthumb} with no
> > +@code{MOVT} instruction available.
> > +
> > 
> >   @end table
> >   
> >   @subsubsection AArch64-specific attributes
> > 
> > diff --git a/gcc/testsuite/gcc.target/arm/pr42574.c
> > b/gcc/testsuite/gcc.target/arm/pr42574.c
> > index
> > 0ccd05f9922c798611e479d97890aa69b180e989..53aea6224be89d2d771a22f8ecb39727
> > 6f586234 100644
> > --- a/gcc/testsuite/gcc.target/arm/pr42574.c
> > +++ b/gcc/testsuite/gcc.target/arm/pr42574.c
> > @@ -1,5 +1,5 @@
> > 
> >   /* { dg-options "-mthumb -Os -fpic" }  */
> > 
> > -/* { dg-require-effective-target arm_thumb1_ok } */
> > +/* { dg-require-effective-target arm_thumb1_movt_ko } */
> > 
> >   /* { dg-require-effective-target fpic } */
> >   /* Make sure the address of glob.c is calculated only once and using
> >   
> >      a logical shift for the offset (200<<1).  */
> > 
> > diff --git a/gcc/testsuite/lib/target-supports.exp
> > b/gcc/testsuite/lib/target- supports.exp
> > index
> > 46352b90de7202960116d93523b017d5dc4a1423..f5d73ad2620fa35f0091a890bca63c7d
> > 35de1a85 100644
> > --- a/gcc/testsuite/lib/target-supports.exp
> > +++ b/gcc/testsuite/lib/target-supports.exp
> > @@ -3329,6 +3329,23 @@ proc check_effective_target_arm_cortex_m { } {
> > 
> >       } "-mthumb"]
> >   
> >   }
> > 
> > +# Return 1 if this is an ARM target where -mthumb causes Thumb-1 to be
> > +# used and no movt/movw instructions to be available.
> > +
> > +proc check_effective_target_arm_thumb1_movt_ko {} {
> > +    if [check_effective_target_arm_thumb1_ok] {
> > +   return [expr ![check_no_compiler_messages arm_movt object {
> > +       int
> > +       foo (void)
> > +       {
> > +         asm ("movt r0, #42");
> > +       }
> > +   } "-mthumb"]]
> > +    } else {
> > +   return 0
> > +    }
> > +}
> > +
> > 
> >   # Return 1 if this compilation turns on string_ops_prefer_neon on.
> >   
> >   proc check_effective_target_arm_tune_string_ops_prefer_neon { } {
> > 
> > Best regards,
> > 
> > Thomas
> > 
> >> On 17/05/16 11:13, Thomas Preudhomme wrote:
> >>> Ping?
> >>> 
> >>> *** gcc/ChangeLog ***
> >>> 
> >>> 2015-11-13  Thomas Preud'homme  <thomas.preudho...@arm.com>
> >>> 
> >>>           * config/arm/arm.h (TARGET_HAVE_MOVT): Include ARMv8-M as
> >>>           having
> >>>           MOVT.
> >>>           * config/arm/arm.c (arm_arch_name): (const_ok_for_op): Check
> >>>           MOVT/MOVW
> >>>           availability with TARGET_HAVE_MOVT.
> >>>           (thumb_legitimate_constant_p): Legalize high part of a
> >>>           label_ref
> >>>           as a
> >>>           constant.
> >> 
> >> I don't think "Legalize" is the right word here. How about "Strip the
> >> HIGH
> >> part of a label_ref"?
> >> 
> >>>           (thumb1_rtx_costs): Also return 0 if setting a half word
> >>>           constant
> >>>           and
> >>>           movw is available.
> >>>           (thumb1_size_rtx_costs): Make set of half word constant also
> >>>           cost
> >>>           1
> >>>           extra instruction if MOVW is available.  Make constant with
> >>>           bottom
> >>> 
> >>> half
> >>> 
> >>>           word zero cost 2 instruction if MOVW is available.
> >>>           * config/arm/arm.md (define_attr "arch"): Add v8mb.
> >>>           (define_attr "arch_enabled"): Set to yes if arch value is v8mb
> >>>           and
> >>>           target is ARMv8-M Baseline.
> >>>           * config/arm/thumb1.md (thumb1_movdi_insn): Add ARMv8-M
> >>>           Baseline
> >>>           only
> >>>           alternative for constants satisfying j constraint.
> >>>           (thumb1_movsi_insn): Likewise.
> >>>           (movsi splitter for K alternative): Tighten condition to not
> >>>           trigger
> >>>           if movt is available and j constraint is satisfied.
> >>>           (Pe immediate splitter): Likewise.
> >>>           (thumb1_movhi_insn): Add ARMv8-M Baseline only alternative for
> >>>           constant fitting in an halfword to use movw.
> >> 
> >> Please use 'MOVW' consistently in the ChangeLog rather than the lowercase
> >> 'movw'
> >> 
> >>>           * doc/sourcebuild.texi (arm_thumb1_movt_ko): Document new ARM
> >>>           effective target.
> >>> 
> >>> *** gcc/testsuite/ChangeLog ***
> >>> 
> >>> 2015-11-13  Thomas Preud'homme  <thomas.preudho...@arm.com>
> >>> 
> >>>           * lib/target-supports.exp
> >>>           (check_effective_target_arm_thumb1_movt_ko):
> >>>           Define effective target.
> >>>           * gcc.target/arm/pr42574.c: Require arm_thumb1_movt_ko instead
> >>>           of
> >>>           arm_thumb1_ok as effective target to exclude ARMv8-M Baseline.
> >>> 
> >>> diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
> >>> index
> >>> 47216b4a1959ccdb18e329db411bf7f941e67163..f42e996e5a7ce979fe406b8261d50f
> >>> b2
> >>> ba005f6b 100644
> >>> --- a/gcc/config/arm/arm.h
> >>> +++ b/gcc/config/arm/arm.h
> >>> @@ -269,7 +269,7 @@ extern void
> >>> (*arm_lang_output_object_attributes_hook)
> >>> (void);
> >>> 
> >>>    #define TARGET_HAVE_LDACQ      (TARGET_ARM_ARCH >= 8 && arm_arch_notm)
> >>>    
> >>>    /* Nonzero if this chip provides the movw and movt instructions.  */
> >>> 
> >>> -#define TARGET_HAVE_MOVT (arm_arch_thumb2)
> >>> +#define TARGET_HAVE_MOVT (arm_arch_thumb2 || arm_arch8)
> >>> 
> >>>    /* Nonzero if integer division instructions supported.  */
> >>>    #define TARGET_IDIV    ((TARGET_ARM && arm_arch_arm_hwdiv)     \
> >>> 
> >>> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> >>> index
> >>> d75a34f10d5ed22cff0a0b5d3ad433f111b059ee..13b4b71ac8f9c1da8ef1945f7ff698
> >>> 5c
> >>> a59f6832 100644
> >>> --- a/gcc/config/arm/arm.c
> >>> +++ b/gcc/config/arm/arm.c
> >>> @@ -8220,6 +8220,12 @@ arm_legitimate_constant_p_1 (machine_mode, rtx x)
> >>> 
> >>>    static bool
> >>>    thumb_legitimate_constant_p (machine_mode mode ATTRIBUTE_UNUSED, rtx
> >>>    x)
> >>>    {
> >>> 
> >>> +  /* Splitters for TARGET_USE_MOVT call arm_emit_movpair which creates
> >>> high +     RTX.  These RTX must therefore be allowed for Thumb-1 so that
> >>> when run +     for ARMv8-M baseline or later the result is valid.  */
> >>> +  if (TARGET_HAVE_MOVT && GET_CODE (x) == HIGH)
> >>> +    x = XEXP (x, 0);
> >>> +
> >>> 
> >>>      return (CONST_INT_P (x)
> >>>      
> >>>             || CONST_DOUBLE_P (x)
> >>>             || CONSTANT_ADDRESS_P (x)
> >>> 
> >>> @@ -8306,7 +8312,8 @@ thumb1_rtx_costs (rtx x, enum rtx_code code, enum
> >>> rtx_code outer)
> >>> 
> >>>        case CONST_INT:
> >>>          if (outer == SET)
> >>>           
> >>>           {
> >>> 
> >>> -   if ((unsigned HOST_WIDE_INT) INTVAL (x) < 256)
> >>> +   if ((unsigned HOST_WIDE_INT) INTVAL (x) < 256
> >>> +       || (TARGET_HAVE_MOVT && !(INTVAL (x) & 0xffff0000)))
> >>> 
> >>>               return 0;
> >> 
> >> Since you're modifying this line please replace (unsigned HOST_WIDE_INT)
> >> INTVAL (x) with UINTVAL (x).
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 615065447b43ef44202a892a938bc7c8a2425222..269611060ec2f15047b4976d412b8c5aa2797005 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -268,8 +268,8 @@ extern void (*arm_lang_output_object_attributes_hook)(void);
 /* Nonzero if this chip supports load-acquire and store-release.  */
 #define TARGET_HAVE_LDACQ	(TARGET_ARM_ARCH >= 8 && arm_arch_notm)
 
-/* Nonzero if this chip provides the MOVW and MOVW instructions.  */
-#define TARGET_HAVE_MOVT	(arm_arch_thumb2)
+/* Nonzero if this chip provides the MOVW and MOVT instructions.  */
+#define TARGET_HAVE_MOVT	(arm_arch_thumb2 || arm_arch8)
 
 /* Nonzero if integer division instructions supported.  */
 #define TARGET_IDIV	((TARGET_ARM && arm_arch_arm_hwdiv)	\
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 109792dbf4e8b7ab130abdbc5622b71953b70df2..eea1960190a65ea9853c7ed7d7a3cfa9dd9c65ec 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -8225,6 +8225,12 @@ arm_legitimate_constant_p_1 (machine_mode, rtx x)
 static bool
 thumb_legitimate_constant_p (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
 {
+  /* Splitters for TARGET_USE_MOVT call arm_emit_movpair which creates high
+     RTX.  These RTX must therefore be allowed for Thumb-1 so that when run
+     for ARMv8-M Baseline or later the result is valid.  */
+  if (TARGET_HAVE_MOVT && GET_CODE (x) == HIGH)
+    x = XEXP (x, 0);
+
   return (CONST_INT_P (x)
 	  || CONST_DOUBLE_P (x)
 	  || CONSTANT_ADDRESS_P (x)
@@ -8311,7 +8317,9 @@ thumb1_rtx_costs (rtx x, enum rtx_code code, enum rtx_code outer)
     case CONST_INT:
       if (outer == SET)
 	{
-	  if ((unsigned HOST_WIDE_INT) INTVAL (x) < 256)
+	  if (UINTVAL (x) < 256
+	      /* 16-bit constant.  */
+	      || (TARGET_HAVE_MOVT && !(INTVAL (x) & 0xffff0000)))
 	    return 0;
 	  if (thumb_shiftable_const (INTVAL (x)))
 	    return COSTS_N_INSNS (2);
@@ -9014,7 +9022,7 @@ static inline int
 thumb1_size_rtx_costs (rtx x, enum rtx_code code, enum rtx_code outer)
 {
   machine_mode mode = GET_MODE (x);
-  int words;
+  int words, cost;
 
   switch (code)
     {
@@ -9060,17 +9068,26 @@ thumb1_size_rtx_costs (rtx x, enum rtx_code code, enum rtx_code outer)
       /* A SET doesn't have a mode, so let's look at the SET_DEST to get
 	 the mode.  */
       words = ARM_NUM_INTS (GET_MODE_SIZE (GET_MODE (SET_DEST (x))));
-      return COSTS_N_INSNS (words)
-	     + COSTS_N_INSNS (1) * (satisfies_constraint_J (SET_SRC (x))
-				    || satisfies_constraint_K (SET_SRC (x))
-				       /* thumb1_movdi_insn.  */
-				    || ((words > 1) && MEM_P (SET_SRC (x))));
+      cost = COSTS_N_INSNS (words);
+      if (satisfies_constraint_J (SET_SRC (x))
+	  || satisfies_constraint_K (SET_SRC (x))
+	     /* Too big an immediate for a 2-byte mov, using MOVT.  */
+	  || (UINTVAL (SET_SRC (x)) >= 256
+	      && TARGET_HAVE_MOVT
+	      && satisfies_constraint_j (SET_SRC (x)))
+	     /* thumb1_movdi_insn.  */
+	  || ((words > 1) && MEM_P (SET_SRC (x))))
+	cost += COSTS_N_INSNS (1);
+      return cost;
 
     case CONST_INT:
       if (outer == SET)
         {
           if (UINTVAL (x) < 256)
             return COSTS_N_INSNS (1);
+	  /* movw is 4byte long.  */
+	  if (TARGET_HAVE_MOVT && !(INTVAL (x) & 0xffff0000))
+	    return COSTS_N_INSNS (2);
 	  /* See split "TARGET_THUMB1 && satisfies_constraint_J".  */
 	  if (INTVAL (x) >= -255 && INTVAL (x) <= -1)
             return COSTS_N_INSNS (2);
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 45796578af061c3259ae02b1b403d81ed7b03807..1e6788f1180f9202b8aa06b244b7d1d07fc9ded0 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -118,10 +118,10 @@
 ; This can be "a" for ARM, "t" for either of the Thumbs, "32" for
 ; TARGET_32BIT, "t1" or "t2" to specify a specific Thumb mode.  "v6"
 ; for ARM or Thumb-2 with arm_arch6, and nov6 for ARM without
-; arm_arch6.  "v6t2" for Thumb-2 with arm_arch6.  This attribute is
-; used to compute attribute "enabled", use type "any" to enable an
-; alternative in all cases.
-(define_attr "arch" "any,a,t,32,t1,t2,v6,nov6,v6t2,neon_for_64bits,avoid_neon_for_64bits,iwmmxt,iwmmxt2,armv6_or_vfpv3,neon"
+; arm_arch6.  "v6t2" for Thumb-2 with arm_arch6 and "v8mb" for ARMv8-M
+; Baseline.  This attribute is used to compute attribute "enabled",
+; use type "any" to enable an alternative in all cases.
+(define_attr "arch" "any,a,t,32,t1,t2,v6,nov6,v6t2,v8mb,neon_for_64bits,avoid_neon_for_64bits,iwmmxt,iwmmxt2,armv6_or_vfpv3,neon"
   (const_string "any"))
 
 (define_attr "arch_enabled" "no,yes"
@@ -160,6 +160,10 @@
 	      (match_test "TARGET_32BIT && arm_arch6 && arm_arch_thumb2"))
 	 (const_string "yes")
 
+	 (and (eq_attr "arch" "v8mb")
+	      (match_test "TARGET_THUMB1 && arm_arch8"))
+	 (const_string "yes")
+
 	 (and (eq_attr "arch" "avoid_neon_for_64bits")
 	      (match_test "TARGET_NEON")
 	      (not (match_test "TARGET_PREFER_NEON_64BITS")))
@@ -5699,12 +5703,15 @@
 ;; LO_SUM adds in the high bits.  Fortunately these are opaque operations
 ;; so this does not matter.
 (define_insn "*arm_movt"
-  [(set (match_operand:SI 0 "nonimmediate_operand" "=r")
-	(lo_sum:SI (match_operand:SI 1 "nonimmediate_operand" "0")
-		   (match_operand:SI 2 "general_operand"      "i")))]
+  [(set (match_operand:SI 0 "nonimmediate_operand" "=r,r")
+	(lo_sum:SI (match_operand:SI 1 "nonimmediate_operand" "0,0")
+		   (match_operand:SI 2 "general_operand"      "i,i")))]
   "TARGET_HAVE_MOVT && arm_valid_symbolic_address_p (operands[2])"
-  "movt%?\t%0, #:upper16:%c2"
-  [(set_attr "predicable" "yes")
+  "@
+   movt%?\t%0, #:upper16:%c2
+   movt\t%0, #:upper16:%c2"
+  [(set_attr "arch"  "32,v8mb")
+   (set_attr "predicable" "yes")
    (set_attr "predicable_short_it" "no")
    (set_attr "length" "4")
    (set_attr "type" "alu_sreg")]
@@ -10958,13 +10965,16 @@
 ;; We only care about the lower 16 bits of the constant 
 ;; being inserted into the upper 16 bits of the register.
 (define_insn "*arm_movtas_ze" 
-  [(set (zero_extract:SI (match_operand:SI 0 "s_register_operand" "+r")
+  [(set (zero_extract:SI (match_operand:SI 0 "s_register_operand" "+r,r")
                    (const_int 16)
                    (const_int 16))
         (match_operand:SI 1 "const_int_operand" ""))]
   "TARGET_HAVE_MOVT"
-  "movt%?\t%0, %L1"
- [(set_attr "predicable" "yes")
+  "@
+   movt%?\t%0, %L1
+   movt\t%0, %L1"
+ [(set_attr "arch" "32,v8mb")
+  (set_attr "predicable" "yes")
   (set_attr "predicable_short_it" "no")
   (set_attr "length" "4")
   (set_attr "type" "alu_sreg")]
diff --git a/gcc/config/arm/thumb1.md b/gcc/config/arm/thumb1.md
index 035641b3335797cb843a5741d7372492d5a91cfc..b317f1b0637e02f105f10efb18270f4a35801c7c 100644
--- a/gcc/config/arm/thumb1.md
+++ b/gcc/config/arm/thumb1.md
@@ -590,8 +590,8 @@
 ;;; ??? The 'i' constraint looks funny, but it should always be replaced by
 ;;; thumb_reorg with a memory reference.
 (define_insn "*thumb1_movdi_insn"
-  [(set (match_operand:DI 0 "nonimmediate_operand" "=l,l,l,l,>,l, m,*r")
-	(match_operand:DI 1 "general_operand"      "l, I,J,>,l,mi,l,*r"))]
+  [(set (match_operand:DI 0 "nonimmediate_operand" "=l,l,l,r,l,>,l, m,*r")
+	(match_operand:DI 1 "general_operand"      "l, I,J,j,>,l,mi,l,*r"))]
   "TARGET_THUMB1
    && (   register_operand (operands[0], DImode)
        || register_operand (operands[1], DImode))"
@@ -610,36 +610,41 @@
       operands[1] = GEN_INT (- INTVAL (operands[1]));
       return \"movs\\t%Q0, %1\;rsbs\\t%Q0, %Q0, #0\;asrs\\t%R0, %Q0, #31\";
     case 3:
-      return \"ldmia\\t%1, {%0, %H0}\";
+      gcc_assert (TARGET_HAVE_MOVT);
+      return \"movw\\t%Q0, %L1\;movs\\tR0, #0\";
     case 4:
-      return \"stmia\\t%0, {%1, %H1}\";
+      return \"ldmia\\t%1, {%0, %H0}\";
     case 5:
-      return thumb_load_double_from_address (operands);
+      return \"stmia\\t%0, {%1, %H1}\";
     case 6:
+      return thumb_load_double_from_address (operands);
+    case 7:
       operands[2] = gen_rtx_MEM (SImode,
 			     plus_constant (Pmode, XEXP (operands[0], 0), 4));
       output_asm_insn (\"str\\t%1, %0\;str\\t%H1, %2\", operands);
       return \"\";
-    case 7:
+    case 8:
       if (REGNO (operands[1]) == REGNO (operands[0]) + 1)
 	return \"mov\\t%0, %1\;mov\\t%H0, %H1\";
       return \"mov\\t%H0, %H1\;mov\\t%0, %1\";
     }
   }"
-  [(set_attr "length" "4,4,6,2,2,6,4,4")
-   (set_attr "type" "multiple,multiple,multiple,load2,store2,load2,store2,multiple")
-   (set_attr "pool_range" "*,*,*,*,*,1018,*,*")]
+  [(set_attr "length" "4,4,6,6,2,2,6,4,4")
+   (set_attr "type" "multiple,multiple,multiple,multiple,load2,store2,load2,store2,multiple")
+   (set_attr "arch" "t1,t1,t1,v8mb,t1,t1,t1,t1,t1")
+   (set_attr "pool_range" "*,*,*,*,*,*,1018,*,*")]
 )
 
 (define_insn "*thumb1_movsi_insn"
-  [(set (match_operand:SI 0 "nonimmediate_operand" "=l,l,l,l,l,>,l, m,*l*h*k")
-	(match_operand:SI 1 "general_operand"      "l, I,J,K,>,l,mi,l,*l*h*k"))]
+  [(set (match_operand:SI 0 "nonimmediate_operand" "=l,l,r,l,l,l,>,l, m,*l*h*k")
+	(match_operand:SI 1 "general_operand"      "l, I,j,J,K,>,l,mi,l,*l*h*k"))]
   "TARGET_THUMB1
    && (   register_operand (operands[0], SImode)
        || register_operand (operands[1], SImode))"
   "@
    movs	%0, %1
    movs	%0, %1
+   movw	%0, %1
    #
    #
    ldmia\\t%1, {%0}
@@ -647,10 +652,11 @@
    ldr\\t%0, %1
    str\\t%1, %0
    mov\\t%0, %1"
-  [(set_attr "length" "2,2,4,4,2,2,2,2,2")
-   (set_attr "type" "mov_reg,mov_imm,multiple,multiple,load1,store1,load1,store1,mov_reg")
-   (set_attr "pool_range" "*,*,*,*,*,*,1018,*,*")
-   (set_attr "conds" "set,clob,*,*,nocond,nocond,nocond,nocond,nocond")])
+  [(set_attr "length" "2,2,4,4,4,2,2,2,2,2")
+   (set_attr "type" "mov_reg,mov_imm,mov_imm,multiple,multiple,load1,store1,load1,store1,mov_reg")
+   (set_attr "pool_range" "*,*,*,*,*,*,*,1018,*,*")
+   (set_attr "arch" "t1,t1,v8mb,t1,t1,t1,t1,t1,t1,t1")
+   (set_attr "conds" "set,clob,nocond,*,*,nocond,nocond,nocond,nocond,nocond")])
 
 ; Split the load of 64-bit constant into two loads for high and low 32-bit parts respectively
 ; to see if we can load them in fewer instructions or fewer cycles.
@@ -687,7 +693,8 @@
 (define_split
   [(set (match_operand:SI 0 "register_operand" "")
 	(match_operand:SI 1 "const_int_operand" ""))]
-  "TARGET_THUMB1 && satisfies_constraint_K (operands[1])"
+  "TARGET_THUMB1 && satisfies_constraint_K (operands[1])
+   && !(TARGET_HAVE_MOVT && satisfies_constraint_j (operands[1]))"
   [(set (match_dup 2) (match_dup 1))
    (set (match_dup 0) (ashift:SI (match_dup 2) (match_dup 3)))]
   "
@@ -714,7 +721,8 @@
 (define_split
   [(set (match_operand:SI 0 "register_operand" "")
 	(match_operand:SI 1 "const_int_operand" ""))]
-  "TARGET_THUMB1 && satisfies_constraint_Pe (operands[1])"
+  "TARGET_THUMB1 && satisfies_constraint_Pe (operands[1])
+   && !(TARGET_HAVE_MOVT && satisfies_constraint_j (operands[1]))"
   [(set (match_dup 2) (match_dup 1))
    (set (match_dup 0) (plus:SI (match_dup 2) (match_dup 3)))]
   "
@@ -726,8 +734,8 @@
 )
 
 (define_insn "*thumb1_movhi_insn"
-  [(set (match_operand:HI 0 "nonimmediate_operand" "=l,l,m,l*r,*h,l")
-	(match_operand:HI 1 "general_operand"       "l,m,l,k*h,*r,I"))]
+  [(set (match_operand:HI 0 "nonimmediate_operand" "=l,l,m,l*r,*h,l,r")
+	(match_operand:HI 1 "general_operand"       "l,m,l,k*h,*r,I,n"))]
   "TARGET_THUMB1
    && (   register_operand (operands[0], HImode)
        || register_operand (operands[1], HImode))"
@@ -739,6 +747,8 @@
     case 3: return \"mov	%0, %1\";
     case 4: return \"mov	%0, %1\";
     case 5: return \"movs	%0, %1\";
+    case 6: gcc_assert (TARGET_HAVE_MOVT);
+	    return \"movw	%0, %L1\";
     default: gcc_unreachable ();
     case 1:
       /* The stack pointer can end up being taken as an index register.
@@ -758,9 +768,10 @@
 	}
       return \"ldrh	%0, %1\";
     }"
-  [(set_attr "length" "2,4,2,2,2,2")
-   (set_attr "type" "alus_imm,load1,store1,mov_reg,mov_reg,mov_imm")
-   (set_attr "conds" "clob,nocond,nocond,nocond,nocond,clob")])
+  [(set_attr "length" "2,4,2,2,2,2,4")
+   (set_attr "type" "alus_imm,load1,store1,mov_reg,mov_reg,mov_imm,mov_imm")
+   (set_attr "arch" "t1,t1,t1,t1,t1,t1,v8mb")
+   (set_attr "conds" "clob,nocond,nocond,nocond,nocond,clob,nocond")])
 
 (define_expand "thumb_movhi_clobber"
   [(set (match_operand:HI     0 "memory_operand"   "")
diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi
index 0c03920cbec090b07f2559d6471c6eac9bb0c18a..2735daf93d4ad07e8554fafd3cb3408c217e9f8f 100644
--- a/gcc/doc/sourcebuild.texi
+++ b/gcc/doc/sourcebuild.texi
@@ -1604,6 +1604,10 @@ ARM target supports acquire-release instructions.
 ARM target prefers @code{LDRD} and @code{STRD} instructions over
 @code{LDM} and @code{STM} instructions.
 
+@item arm_thumb1_movt_ok
+ARM target generates Thumb-1 code for @code{-mthumb} with @code{MOVW}
+and @code{MOVT} instructions available.
+
 @end table
 
 @subsubsection AArch64-specific attributes
diff --git a/gcc/testsuite/gcc.target/arm/movdi_movw.c b/gcc/testsuite/gcc.target/arm/movdi_movw.c
new file mode 100644
index 0000000000000000000000000000000000000000..0f6b839da614c56766e92e3da125551df47890fc
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/movdi_movw.c
@@ -0,0 +1,10 @@
+/* { dg-do compile { target { arm_thumb2 || arm_thumb1_movt_ok } } } */
+/* { dg-options "-O2" } */
+
+long long
+movdi (int a)
+{
+  return 0xF0F0;
+}
+
+/* { dg-final { scan-assembler-times "movw\tr0, #61680" 1 } } */
diff --git a/gcc/testsuite/gcc.target/arm/movhi_movw.c b/gcc/testsuite/gcc.target/arm/movhi_movw.c
new file mode 100644
index 0000000000000000000000000000000000000000..b097a8a019c74507f0c182af6ba5cf526369564b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/movhi_movw.c
@@ -0,0 +1,10 @@
+/* { dg-do compile { target { arm_thumb2 || arm_thumb1_movt_ok } } } */
+/* { dg-options "-O2" } */
+
+short
+movsi (void)
+{
+  return (short) 0x7070;
+}
+
+/* { dg-final { scan-assembler-times "movw\tr0, #28784" 1 } } */
diff --git a/gcc/testsuite/gcc.target/arm/movsi_movw.c b/gcc/testsuite/gcc.target/arm/movsi_movw.c
new file mode 100644
index 0000000000000000000000000000000000000000..d50906e76ab412ead71ff576d2f28d520234f58d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/movsi_movw.c
@@ -0,0 +1,10 @@
+/* { dg-do compile { target { arm_thumb2 || arm_thumb1_movt_ok } } } */
+/* { dg-options "-O2" } */
+
+int
+movsi (void)
+{
+  return 0xF0F0;
+}
+
+/* { dg-final { scan-assembler-times "movw\tr0, #61680" 1 } } */
diff --git a/gcc/testsuite/gcc.target/arm/pr42574.c b/gcc/testsuite/gcc.target/arm/pr42574.c
index 0ccd05f9922c798611e479d97890aa69b180e989..e3476f37788a2b3144454aef04a9b45c0b4ac398 100644
--- a/gcc/testsuite/gcc.target/arm/pr42574.c
+++ b/gcc/testsuite/gcc.target/arm/pr42574.c
@@ -1,5 +1,5 @@
+/* { dg-do compile { arm_thumb1_ok && { ! arm_thumb1_movt_ok } } } */
 /* { dg-options "-mthumb -Os -fpic" }  */
-/* { dg-require-effective-target arm_thumb1_ok } */
 /* { dg-require-effective-target fpic } */
 /* Make sure the address of glob.c is calculated only once and using
    a logical shift for the offset (200<<1).  */
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index ace1b32f755d033eb035b217e422bdc5f4dc2dea..f678eaa86731ba552d4e528d326c90a5ae0bbfaf 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -3329,6 +3329,23 @@ proc check_effective_target_arm_cortex_m { } {
     } "-mthumb"]
 }
 
+# Return 1 if this is an ARM target where -mthumb causes Thumb-1 to be
+# used and MOVT/MOVW instructions to be available.
+
+proc check_effective_target_arm_thumb1_movt_ok {} {
+    if [check_effective_target_arm_thumb1_ok] {
+	return [check_no_compiler_messages arm_movt object {
+	    int
+	    foo (void)
+	    {
+	      asm ("movt r0, #42");
+	    }
+	} "-mthumb"]
+    } else {
+	return 0
+    }
+}
+
 # Return 1 if this compilation turns on string_ops_prefer_neon on.
 
 proc check_effective_target_arm_tune_string_ops_prefer_neon { } {

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