Hi Richard, Hi Ramana,
The ARM backend has some problems compiling for the old ARMv3
architecture. See:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62254
for an example of this. v3 is very old now, and I am not sure how
much interest there is in continuing to support it, but I am trying to
help reduce the gcc priority bug list, so here goes...
The attached patch fixes the problem, albeit not in a very subtle way.
The problem is that arm_reload_[out|in]_hi is being called for a
register->register move because the v3 architecture does not support
16-bit register moves. Rather than trace the problem back to the real
source and fix it, I chose to just allow the reload functions to
generate an SImode register move instead. Probably not the best
solution, but it appears to work.
The attached patch also includes the test cases derived from PR 62254
and PR 69610 (which is a duplicate of PR 62254). Including all three
tests might be overkill, but it seemed like a good idea to be a little
bit paranoid, just in case.
Whilst testing the patch I also discovered that interworking is
enabled by default, which is a problem for v3 code generation, so I
added a fix to (silently) disable interworking if the target
architecture does not support Thumb instructions.
Any comments or criticisms before I apply the patch ?
Cheers
Nick
gcc/ChangeLog
2016-02-16 Nick Clifton <ni...@redhat.com>
PR target/62554
PR target/69610
* config/arm/arm.c (arm_option_override_internal): Disable
interworking if the target does not support thumb instructions.
(arm_reload_in_hi): Handle the case where a register to register
move needs reloading because there is no simple pattern to handle
it.
(arm_reload_out_hi): Likewise.
gcc/testsuite/ChangeLog
2016-02-16 Nick Clifton <ni...@redhat.com>
PR target/62554
PR target/69610
* gcc.target/arm/pr62554.c: New test.
* gcc.target/arm/pr69610-1.c: New test.
* gcc.target/arm/pr69610-2.c: New test.
Index: gcc/config/arm/arm.c
===================================================================
--- gcc/config/arm/arm.c (revision 233443)
+++ gcc/config/arm/arm.c (working copy)
@@ -2874,6 +2874,14 @@
{
arm_override_options_after_change_1 (opts);
+ if (TARGET_INTERWORK && !ARM_FSET_HAS_CPU1 (insn_flags, FL_THUMB))
+ {
+ /* The default is to enable interworking, so this warning message would
+ be confusing to users who have just compiled with, eg, -march=armv3. */
+ /* warning (0, "ignoring -minterwork because target CPU does not support THUMB"); */
+ opts->x_target_flags &= ~MASK_INTERWORK;
+ }
+
if (TARGET_THUMB_P (opts->x_target_flags)
&& !(ARM_FSET_HAS_CPU1 (insn_flags, FL_THUMB)))
{
@@ -15440,6 +15448,17 @@
else
/* The slot is out of range, or was dressed up in a SUBREG. */
base = reg_equiv_address (REGNO (ref));
+
+ /* PR 62554: If there is no equivalent memory location then just move
+ the value as an SImode register move. This happens when the target
+ architecure variant does not have an HImode register move. */
+ if (base == NULL)
+ {
+ gcc_assert (REG_P (operands[0]));
+ emit_insn (gen_movsi (gen_rtx_SUBREG (SImode, operands[0], 0),
+ gen_rtx_SUBREG (SImode, ref, 0)));
+ return;
+ }
}
else
base = find_replacement (&XEXP (ref, 0));
@@ -15557,6 +15576,17 @@
else
/* The slot is out of range, or was dressed up in a SUBREG. */
base = reg_equiv_address (REGNO (ref));
+
+ /* PR 62554: If there is no equivalent memory location then just move
+ the value as an SImode register move. This happens when the target
+ architecure variant does not have an HImode register move. */
+ if (base == NULL)
+ {
+ gcc_assert (REG_P (outval));
+ emit_insn (gen_movsi (gen_rtx_SUBREG (SImode, ref, 0),
+ gen_rtx_SUBREG (SImode, outval, 0)));
+ return;
+ }
}
else
base = find_replacement (&XEXP (ref, 0));
@@ -19619,6 +19649,7 @@
break;
case ARM_FT_INTERWORKED:
+ gcc_assert (arm_arch5 || arm_arch4t);
sprintf (instr, "bx%s\t%%|lr", conditional);
break;
--- /dev/null 2016-02-16 08:27:18.513962320 +0000
+++ gcc/testsuite/gcc.target/arm/pr62254.c 2016-02-16 16:47:30.479378118 +0000
@@ -0,0 +1,50 @@
+/* Check that pre ARMv4 compilation still works. */
+/* { dg-do compile } */
+/* { dg-options "-marm -march=armv3 -O" } */
+
+typedef struct
+{
+ char bits;
+ short val;
+} code;
+
+union uu
+{
+ short us;
+ char b[2];
+};
+
+int a, b, c, f, g, h;
+code *d;
+
+code e;
+
+int
+fn1 (void)
+{
+ char i;
+ do
+ if (e.bits)
+ {
+ dodist:
+ f = c;
+ if (e.bits & 6)
+ {
+ ++i;
+ if (g)
+ do
+ {
+ union uu j;
+ j.b[1] = a;
+ h = j.us;
+ }
+ while (fn1);
+ }
+ else
+ {
+ e = d[b];
+ goto dodist;
+ }
+ }
+ while (i);
+}
--- /dev/null 2016-02-16 08:27:18.513962320 +0000
+++ gcc/testsuite/gcc.target/arm/pr69610-1.c 2016-02-16 16:51:48.987779288 +0000
@@ -0,0 +1,13 @@
+/* Check that pre ARMv4 compilation still works. */
+/* { dg-do compile } */
+/* { dg-options "-marm -march=armv3 -ftree-ter" } */
+
+typedef unsigned short v16u16 __attribute__ ((vector_size (16)));
+typedef unsigned int v16u32 __attribute__ ((vector_size (16)));
+
+unsigned short
+foo (v16u16 v16u16_1, v16u32 v16u32_1)
+{
+ v16u16_1 += (v16u16) v16u32_1;
+ return v16u16_1[5] + v16u32_1[1];
+}
--- /dev/null 2016-02-16 08:27:18.513962320 +0000
+++ gcc/testsuite/gcc.target/arm/pr69610-2.c 2016-02-16 16:51:27.119660758 +0000
@@ -0,0 +1,32 @@
+/* Check that pre ARMv4 compilation still works. */
+/* { dg-do compile } */
+/* { dg-options "-marm -march=armv3 -O2 -fno-forward-propagate" } */
+
+typedef short v16u16 __attribute__ ((vector_size (16)));
+typedef unsigned v16u32 __attribute__ ((vector_size (16)));
+typedef long long v16u64 __attribute__ ((vector_size (16)));
+
+unsigned
+foo
+ (int
+ u16_0,
+ unsigned
+ u32_0,
+ int
+ u64_0,
+ int
+ u16_1,
+ unsigned
+ u64_1,
+ v16u16
+ v16u16_0,
+ v16u32
+ v16u32_0,
+ v16u64 v16u64_0, v16u16 v16u16_1, v16u32 v16u32_1, v16u64 v16u64_1)
+{
+ v16u16_1[3] -= v16u32_0[0];
+ v16u16_0 -= (v16u16) v16u32_0;
+ return u16_0 + u32_0 + u64_0 + u16_1 +
+ v16u16_0[0] + v16u16_0[2] + v16u16_0[3] + v16u16_0[4] + v16u16_0[5] + v16u32_0[0] + v16u32_0[1] + v16u32_0[3] + v16u64_0[1] +
+ v16u16_1[2] + v16u16_1[3] + v16u16_1[5] + v16u16_1[7] + v16u32_1[0] + v16u32_1[3] + v16u64_1[0] + v16u64_1[1];
+}
