Re: Fix vect_float markup for a couple of tests (PR 83888)

[Richard Sandiford]

Richard Biener  writes:
> On Mon, Jan 22, 2018 at 6:55 PM, Richard Sandiford
>  wrote:
>> vect_float is true for arm*-*-* targets, but the support is only
>> available when -funsafe-math-optimizations is on.  This caused
>> failures in two tests that disable fast-math.
>>
>> The easiest fix seemed to be to add a new target selector for
>> "vect_float without special options".
>>
>> Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu.
>> OK to install?
>
> Ok - so arm float vectors are not IEEE compliant?

Not for subnormals apparently:

; Note that NEON operations don't support the full IEEE 754 standard: in
; particular, denormal values are flushed to zero.  This means that GCC cannot
; use those instructions for autovectorization, etc. unless
; -funsafe-math-optimizations is in effect (in which case flush-to-zero
; behavior is permissible).

Thanks,
Richard

Re: Fix vect_float markup for a couple of tests (PR 83888)

[Richard Biener]

On Mon, Jan 22, 2018 at 6:55 PM, Richard Sandiford
 wrote:
> vect_float is true for arm*-*-* targets, but the support is only
> available when -funsafe-math-optimizations is on.  This caused
> failures in two tests that disable fast-math.
>
> The easiest fix seemed to be to add a new target selector for
> "vect_float without special options".
>
> Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu.
> OK to install?

Ok - so arm float vectors are not IEEE compliant?

Richard.

> Richard
>
>
> 2018-01-22  Richard Sandiford  
>
> gcc/
> PR testsuite/83888
> * doc/sourcebuild.texi (vect_float): Say that the selector
> only describes the situation when -funsafe-math-optimizations is on.
> (vect_float_strict): Document.
>
> gcc/testsuite/
> PR testsuite/83888
> * lib/target-supports.exp (check_effective_target_vect_float): Say
> that the result only holds when -funsafe-math-optimizations is on.
> (check_effective_target_vect_float_strict): New procedure.
> * gcc.dg/vect/no-fast-math-vect16.c: Use vect_float_strict instead
> of vect_float.
> * gcc.dg/vect/vect-reduc-6.c: Likewise.
>
> Index: gcc/doc/sourcebuild.texi
> ===
> --- gcc/doc/sourcebuild.texi2018-01-22 17:51:03.860579049 +
> +++ gcc/doc/sourcebuild.texi2018-01-22 17:54:02.172848564 +
> @@ -1403,7 +1403,13 @@ The target's preferred vector alignment
>  alignment.
>
>  @item vect_float
> -Target supports hardware vectors of @code{float}.
> +Target supports hardware vectors of @code{float} when
> +@option{-funsafe-math-optimizations} is in effect.
> +
> +@item vect_float_strict
> +Target supports hardware vectors of @code{float} when
> +@option{-funsafe-math-optimizations} is not in effect.
> +This implies @code{vect_float}.
>
>  @item vect_int
>  Target supports hardware vectors of @code{int}.
> Index: gcc/testsuite/lib/target-supports.exp
> ===
> --- gcc/testsuite/lib/target-supports.exp   2018-01-22 17:51:03.817580787 
> +
> +++ gcc/testsuite/lib/target-supports.exp   2018-01-22 17:54:02.173848531 
> +
> @@ -5492,7 +5492,8 @@ proc check_effective_target_vect_long {
>  return $answer
>  }
>
> -# Return 1 if the target supports hardware vectors of float, 0 otherwise.
> +# Return 1 if the target supports hardware vectors of float when
> +# -funsafe-math-optimizations is enabled, 0 otherwise.
>  #
>  # This won't change for different subtargets so cache the result.
>
> @@ -5525,6 +5526,14 @@ proc check_effective_target_vect_float {
>  return $et_vect_float_saved($et_index)
>  }
>
> +# Return 1 if the target supports hardware vectors of float without
> +# -funsafe-math-optimizations being enabled, 0 otherwise.
> +
> +proc check_effective_target_vect_float_strict { } {
> +return [expr { [check_effective_target_vect_float]
> +  && ![istarget arm*-*-*] }]
> +}
> +
>  # Return 1 if the target supports hardware vectors of double, 0 otherwise.
>  #
>  # This won't change for different subtargets so cache the result.
> Index: gcc/testsuite/gcc.dg/vect/no-fast-math-vect16.c
> ===
> --- gcc/testsuite/gcc.dg/vect/no-fast-math-vect16.c 2018-01-13 
> 18:01:15.293116922 +
> +++ gcc/testsuite/gcc.dg/vect/no-fast-math-vect16.c 2018-01-22 
> 17:54:02.172848564 +
> @@ -1,4 +1,4 @@
> -/* { dg-require-effective-target vect_float } */
> +/* { dg-require-effective-target vect_float_strict } */
>
>  #include 
>  #include "tree-vect.h"
> Index: gcc/testsuite/gcc.dg/vect/vect-reduc-6.c
> ===
> --- gcc/testsuite/gcc.dg/vect/vect-reduc-6.c2018-01-13 18:01:15.294116882 
> +
> +++ gcc/testsuite/gcc.dg/vect/vect-reduc-6.c2018-01-22 17:54:02.172848564 
> +
> @@ -1,4 +1,4 @@
> -/* { dg-require-effective-target vect_float } */
> +/* { dg-require-effective-target vect_float_strict } */
>  /* { dg-additional-options "-fno-fast-math" } */
>
>  #include 

Fix vect_float markup for a couple of tests (PR 83888)

[Richard Sandiford]

vect_float is true for arm*-*-* targets, but the support is only
available when -funsafe-math-optimizations is on.  This caused
failures in two tests that disable fast-math.

The easiest fix seemed to be to add a new target selector for
"vect_float without special options".

Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu.
OK to install?

Richard


2018-01-22  Richard Sandiford  

gcc/
PR testsuite/83888
* doc/sourcebuild.texi (vect_float): Say that the selector
only describes the situation when -funsafe-math-optimizations is on.
(vect_float_strict): Document.

gcc/testsuite/
PR testsuite/83888
* lib/target-supports.exp (check_effective_target_vect_float): Say
that the result only holds when -funsafe-math-optimizations is on.
(check_effective_target_vect_float_strict): New procedure.
* gcc.dg/vect/no-fast-math-vect16.c: Use vect_float_strict instead
of vect_float.
* gcc.dg/vect/vect-reduc-6.c: Likewise.

Index: gcc/doc/sourcebuild.texi
===
--- gcc/doc/sourcebuild.texi2018-01-22 17:51:03.860579049 +
+++ gcc/doc/sourcebuild.texi2018-01-22 17:54:02.172848564 +
@@ -1403,7 +1403,13 @@ The target's preferred vector alignment
 alignment.
 
 @item vect_float
-Target supports hardware vectors of @code{float}.
+Target supports hardware vectors of @code{float} when
+@option{-funsafe-math-optimizations} is in effect.
+
+@item vect_float_strict
+Target supports hardware vectors of @code{float} when
+@option{-funsafe-math-optimizations} is not in effect.
+This implies @code{vect_float}.
 
 @item vect_int
 Target supports hardware vectors of @code{int}.
Index: gcc/testsuite/lib/target-supports.exp
===
--- gcc/testsuite/lib/target-supports.exp   2018-01-22 17:51:03.817580787 
+
+++ gcc/testsuite/lib/target-supports.exp   2018-01-22 17:54:02.173848531 
+
@@ -5492,7 +5492,8 @@ proc check_effective_target_vect_long {
 return $answer
 }
 
-# Return 1 if the target supports hardware vectors of float, 0 otherwise.
+# Return 1 if the target supports hardware vectors of float when
+# -funsafe-math-optimizations is enabled, 0 otherwise.
 #
 # This won't change for different subtargets so cache the result.
 
@@ -5525,6 +5526,14 @@ proc check_effective_target_vect_float {
 return $et_vect_float_saved($et_index)
 }
 
+# Return 1 if the target supports hardware vectors of float without
+# -funsafe-math-optimizations being enabled, 0 otherwise.
+
+proc check_effective_target_vect_float_strict { } {
+return [expr { [check_effective_target_vect_float]
+  && ![istarget arm*-*-*] }]
+}
+
 # Return 1 if the target supports hardware vectors of double, 0 otherwise.
 #
 # This won't change for different subtargets so cache the result.
Index: gcc/testsuite/gcc.dg/vect/no-fast-math-vect16.c
===
--- gcc/testsuite/gcc.dg/vect/no-fast-math-vect16.c 2018-01-13 
18:01:15.293116922 +
+++ gcc/testsuite/gcc.dg/vect/no-fast-math-vect16.c 2018-01-22 
17:54:02.172848564 +
@@ -1,4 +1,4 @@
-/* { dg-require-effective-target vect_float } */
+/* { dg-require-effective-target vect_float_strict } */
 
 #include 
 #include "tree-vect.h"
Index: gcc/testsuite/gcc.dg/vect/vect-reduc-6.c
===
--- gcc/testsuite/gcc.dg/vect/vect-reduc-6.c2018-01-13 18:01:15.294116882 
+
+++ gcc/testsuite/gcc.dg/vect/vect-reduc-6.c2018-01-22 17:54:02.172848564 
+
@@ -1,4 +1,4 @@
-/* { dg-require-effective-target vect_float } */
+/* { dg-require-effective-target vect_float_strict } */
 /* { dg-additional-options "-fno-fast-math" } */
 
 #include