From d87483015d476a95f521f0c9dcf6988ca889063b Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 24 Dec 2021 12:50:21 -0800
Subject: [PATCH] i386: Check AX input in any_mul_highpart peepholes
When applying peephole optimization to transform
mov imm, %reg0
mov %reg1, %AX_REG
imul %reg0
to
mov imm, %AX_REG
imul %reg1
disable peephole optimization if reg1 == AX_REG.
gcc/
PR target/103785
* config/i386/i386.md: Swap operand order in comments and check
AX input in any_mul_highpart peepholes.
gcc/testsuite/
PR target/103785
* gcc.target/i386/pr103785.c: New test.
---
gcc/config/i386/i386.md | 10 +++++--
gcc/testsuite/gcc.target/i386/pr103785.c | 38 ++++++++++++++++++++++++
2 files changed, 45 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr103785.c
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 284b9507466d..eea5d5d3f012 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -8578,7 +8578,7 @@
(set_attr "mode" "SI")])
;; Highpart multiplication peephole2s to tweak register allocation.
-;; mov %rdx,imm; mov %rax,%rdi; imulq %rdx -> mov %rax,imm; imulq %rdi
+;; mov imm,%rdx; mov %rdi,%rax; imulq %rdx -> mov imm,%rax; imulq %rdi
(define_peephole2
[(set (match_operand:SWI48 0 "general_reg_operand")
(match_operand:SWI48 1 "immediate_operand"))
@@ -8588,7 +8588,8 @@
(any_mul_highpart:SWI48 (match_dup 2) (match_dup 0)))
(clobber (match_dup 2))
(clobber (reg:CC FLAGS_REG))])]
- "REGNO (operands[0]) != REGNO (operands[2])
+ "REGNO (operands[3]) != AX_REG
+ && REGNO (operands[0]) != REGNO (operands[2])
&& REGNO (operands[0]) != REGNO (operands[3])
&& (REGNO (operands[0]) == REGNO (operands[4])
|| peep2_reg_dead_p (3, operands[0]))"
@@ -8608,7 +8609,10 @@
(any_mul_highpart:SI (match_dup 2) (match_dup 0))))
(clobber (match_dup 2))
(clobber (reg:CC FLAGS_REG))])]
- "REGNO (operands[0]) != REGNO (operands[2])
+ "TARGET_64BIT
+ && REGNO (operands[3]) != AX_REG
+ && REGNO (operands[0]) != REGNO (operands[2])
+ && REGNO (operands[2]) != REGNO (operands[3])
&& REGNO (operands[0]) != REGNO (operands[3])
&& (REGNO (operands[0]) == REGNO (operands[4])
|| peep2_reg_dead_p (3, operands[0]))"
diff --git a/gcc/testsuite/gcc.target/i386/pr103785.c b/gcc/testsuite/gcc.target/i386/pr103785.c
new file mode 100644
index 000000000000..5503b965256b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr103785.c
@@ -0,0 +1,38 @@
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include <stdlib.h>
+
+struct wrapper_t
+{
+ long k;
+ long e;
+};
+
+struct wrapper_t **table;
+
+__attribute__ ((weak, regparm (2)))
+void
+update (long k, long e)
+{
+ struct wrapper_t *elmt;
+
+ elmt = table[k % 3079];
+ if (elmt == 0)
+ return;
+ elmt->e = e;
+}
+
+int
+main ()
+{
+ table = (struct wrapper_t **) malloc (20 * sizeof (struct wrapper_t *));
+ for (int i = 0; i < 20; i++)
+ table[i] = (struct wrapper_t *) calloc (sizeof (struct wrapper_t), 1);
+ if (table[10]->e != 0)
+ abort ();
+ update (10, 20);
+ if (table[10]->e != 20)
+ abort ();
+ return 0;
+}
--
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