[gcc r11-7904] aarch64: Prevent use of SIMD fcvtz[su] instruction variant with "nosimd"

[gcc r11-7904] aarch64: Prevent use of SIMD fcvtz[su] instruction variant with "nosimd"

[Richard Sandiford]

https://gcc.gnu.org/g:cc2fda1328ee69b92724d6b3cffb741f07d86047

commit r11-7904-gcc2fda1328ee69b92724d6b3cffb741f07d86047
Author: Mihailo Stojanovic <mihailo.stojanovic@typhoon-hil.com>
Date:   Tue Mar 30 11:42:49 2021 +0100

    aarch64: Prevent use of SIMD fcvtz[su] instruction variant with "nosimd"
    
    Currently, SF->SI and DF->DI conversions on Aarch64 with the "nosimd"
    flag provided sometimes cause the emitting of a vector variant of the
    fcvtz[su] instruction (e.g. fcvtzu s0, s0).
    
    This modifies the corresponding pattern to only select the vector
    variant of the instruction when generating code with SIMD enabled.
    
    gcc/ChangeLog:
    
            * config/aarch64/aarch64.md
            (<optab>_trunc<fcvt_target><GPI:mode>2): Set the "arch"
            attribute to disambiguate between SIMD and FP variants of the
            instruction.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/aarch64/fcvt_nosimd.c: New test.

Diff:
---
 gcc/config/aarch64/aarch64.md                  |  3 ++-
 gcc/testsuite/gcc.target/aarch64/fcvt_nosimd.c | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index b2abb5b5b3c..dd1dc2bd7a8 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -5989,7 +5989,8 @@
   "@
    fcvtz<su>\t%<s>0, %<s>1
    fcvtz<su>\t%<w>0, %<s>1"
-  [(set_attr "type" "neon_fp_to_int_s,f_cvtf2i")]
+  [(set_attr "type" "neon_fp_to_int_s,f_cvtf2i")
+   (set_attr "arch" "simd,fp")]
 )
 
 ;; Convert HF -> SI or DI
diff --git a/gcc/testsuite/gcc.target/aarch64/fcvt_nosimd.c b/gcc/testsuite/gcc.target/aarch64/fcvt_nosimd.c
new file mode 100644
index 00000000000..7b2ab65e307
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/fcvt_nosimd.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-options "-march=armv8-a+nosimd" } */
+
+#include <stdint.h>
+
+uint64_t test_double_to_uint64(double x) {
+  return (uint64_t)x;
+}
+
+int64_t test_double_to_int64(double x) {
+  return (int64_t)x;
+}
+
+uint32_t test_float_to_uint32(float x) {
+  return (uint32_t)x;
+}
+
+int32_t test_float_to_int32(float x) {
+  return (int32_t)x;
+}
+
+/* { dg-final { scan-assembler-not {\tfcvtz[su]\td[0-9]*, d[0-9]*} } } */
+/* { dg-final { scan-assembler-not {\tfcvtz[su]\ts[0-9]*, s[0-9]*} } } */