[gcc r13-2448] i386: avoid zero extension for crc32q

[gcc r13-2448] i386: avoid zero extension for crc32q

[Alexander Monakov]

https://gcc.gnu.org/g:810d9815249451f477d4cbc67b8e4a0819c37faa

commit r13-2448-g810d9815249451f477d4cbc67b8e4a0819c37faa
Author: Alexander Monakov <amonakov@ispras.ru>
Date:   Tue Aug 23 18:42:24 2022 +0300

    i386: avoid zero extension for crc32q
    
    The crc32q instruction takes 64-bit operands, but ignores high 32 bits
    of the destination operand, and zero-extends the result from 32 bits.
    
    Let's model this in the RTL pattern to avoid zero-extension when the
    _mm_crc32_u64 intrinsic is used with a 32-bit type.
    
            PR target/106453
    
    gcc/ChangeLog:
    
            * config/i386/i386.md (sse4_2_crc32di): Model that only low 32
            bits of operand 0 are consumed, and the result is zero-extended
            to 64 bits.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/i386/pr106453.c: New test.

Diff:
---
 gcc/config/i386/i386.md                  |  9 +++++----
 gcc/testsuite/gcc.target/i386/pr106453.c | 13 +++++++++++++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 1aef1af594d..1be9b669909 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -23823,10 +23823,11 @@
 
 (define_insn "sse4_2_crc32di"
   [(set (match_operand:DI 0 "register_operand" "=r")
-	(unspec:DI
-	  [(match_operand:DI 1 "register_operand" "0")
-	   (match_operand:DI 2 "nonimmediate_operand" "rm")]
-	  UNSPEC_CRC32))]
+	(zero_extend:DI
+	  (unspec:SI
+	    [(match_operand:SI 1 "register_operand" "0")
+	     (match_operand:DI 2 "nonimmediate_operand" "rm")]
+	  UNSPEC_CRC32)))]
   "TARGET_64BIT && TARGET_CRC32"
   "crc32{q}\t{%2, %0|%0, %2}"
   [(set_attr "type" "sselog1")
diff --git a/gcc/testsuite/gcc.target/i386/pr106453.c b/gcc/testsuite/gcc.target/i386/pr106453.c
new file mode 100644
index 00000000000..bd2e7282cf6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr106453.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target { ! ia32 } } } */
+/* { dg-options "-O2 -mcrc32 -dp" } */
+/* { dg-final { scan-assembler-not "zero_extendsidi" } } */
+
+#include <immintrin.h>
+#include <stdint.h>
+
+uint32_t f(uint32_t c, uint64_t *p, size_t n)
+{
+    for (size_t i = 0; i < n; i++)
+        c = _mm_crc32_u64(c, p[i]);
+    return c;
+}