Re: [PATCH][Backport][GCC13] match.pd: Only merge truncation with conversion for -fno-signed-zeros

[Richard Biener]

On Mon, Apr 29, 2024 at 5:12 PM Joe Ramsay  wrote:
>
> This optimisation does not honour signed zeros, so should not be
> enabled except with -fno-signed-zeros.
>
> Cherry-pick of 7dd3b2b09cbeb6712ec680a0445cb0ad41070423.
>
> Applies cleanly on releases/gcc-13, regression-tested with no new
> failures.
>
> OK for backport to GCC 13? If so, please commit for me as I do not
> have commit rights in GCC.

I've pushed to 12 and 13.

Richard.

> Thanks,
> Joe
>
> gcc/ChangeLog:
>
> * match.pd: Fix truncation pattern for -fno-signed-zeroes
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/aarch64/no_merge_trunc_signed_zero.c: New test.
> ---
>  gcc/match.pd  |  1 +
>  .../aarch64/no_merge_trunc_signed_zero.c  | 24 +++
>  2 files changed, 25 insertions(+)
>  create mode 100644 
> gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 47e48fa2ca5..dc34e7ead9f 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -4188,6 +4188,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>  (simplify
> (float (fix_trunc @0))
> (if (!flag_trapping_math
> +   && !HONOR_SIGNED_ZEROS (type)
> && types_match (type, TREE_TYPE (@0))
> && direct_internal_fn_supported_p (IFN_TRUNC, type,
>   OPTIMIZE_FOR_BOTH))
> diff --git a/gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c 
> b/gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c
> new file mode 100644
> index 000..b2c93e55567
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c
> @@ -0,0 +1,24 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fno-trapping-math -fsigned-zeros" } */
> +
> +#include 
> +
> +float
> +f1 (float x)
> +{
> +  return (int) rintf(x);
> +}
> +
> +double
> +f2 (double x)
> +{
> +  return (long) rint(x);
> +}
> +
> +/* { dg-final { scan-assembler "frintx\\ts\[0-9\]+, s\[0-9\]+" } } */
> +/* { dg-final { scan-assembler "cvtzs\\ts\[0-9\]+, s\[0-9\]+" } } */
> +/* { dg-final { scan-assembler "scvtf\\ts\[0-9\]+, s\[0-9\]+" } } */
> +/* { dg-final { scan-assembler "frintx\\td\[0-9\]+, d\[0-9\]+" } } */
> +/* { dg-final { scan-assembler "cvtzs\\td\[0-9\]+, d\[0-9\]+" } } */
> +/* { dg-final { scan-assembler "scvtf\\td\[0-9\]+, d\[0-9\]+" } } */
> +
> --
> 2.27.0
>

[PATCH][Backport][GCC13] match.pd: Only merge truncation with conversion for -fno-signed-zeros

[Joe Ramsay]

This optimisation does not honour signed zeros, so should not be
enabled except with -fno-signed-zeros.

Cherry-pick of 7dd3b2b09cbeb6712ec680a0445cb0ad41070423.

Applies cleanly on releases/gcc-13, regression-tested with no new
failures.

OK for backport to GCC 13? If so, please commit for me as I do not
have commit rights in GCC.

Thanks,
Joe

gcc/ChangeLog:

* match.pd: Fix truncation pattern for -fno-signed-zeroes

gcc/testsuite/ChangeLog:

* gcc.target/aarch64/no_merge_trunc_signed_zero.c: New test.
---
 gcc/match.pd  |  1 +
 .../aarch64/no_merge_trunc_signed_zero.c  | 24 +++
 2 files changed, 25 insertions(+)
 create mode 100644 
gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c

diff --git a/gcc/match.pd b/gcc/match.pd
index 47e48fa2ca5..dc34e7ead9f 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -4188,6 +4188,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 (simplify
(float (fix_trunc @0))
(if (!flag_trapping_math
+   && !HONOR_SIGNED_ZEROS (type)
&& types_match (type, TREE_TYPE (@0))
&& direct_internal_fn_supported_p (IFN_TRUNC, type,
  OPTIMIZE_FOR_BOTH))
diff --git a/gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c 
b/gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c
new file mode 100644
index 000..b2c93e55567
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-trapping-math -fsigned-zeros" } */
+
+#include 
+
+float
+f1 (float x)
+{
+  return (int) rintf(x);
+}
+
+double
+f2 (double x)
+{
+  return (long) rint(x);
+}
+
+/* { dg-final { scan-assembler "frintx\\ts\[0-9\]+, s\[0-9\]+" } } */
+/* { dg-final { scan-assembler "cvtzs\\ts\[0-9\]+, s\[0-9\]+" } } */
+/* { dg-final { scan-assembler "scvtf\\ts\[0-9\]+, s\[0-9\]+" } } */
+/* { dg-final { scan-assembler "frintx\\td\[0-9\]+, d\[0-9\]+" } } */
+/* { dg-final { scan-assembler "cvtzs\\td\[0-9\]+, d\[0-9\]+" } } */
+/* { dg-final { scan-assembler "scvtf\\td\[0-9\]+, d\[0-9\]+" } } */
+
-- 
2.27.0