===================================================================
@@ -10339,7 +10339,7 @@
"operands[2] = gen_lowpart (QImode, operands[2]);")
(define_insn_and_split "*<shift_insn><mode>3_doubleword"
- [(set (match_operand:DWI 0 "register_operand" "=r")
+ [(set (match_operand:DWI 0 "register_operand" "=&r")
(any_shiftrt:DWI (match_operand:DWI 1 "register_operand" "0")
(match_operand:QI 2 "nonmemory_operand" "<S>c")))
(clobber (reg:CC FLAGS_REG))]
===================================================================
@@ -0,0 +1,32 @@
+/* { dg-do run } */
+/* { dg-require-effective-target int128 } */
+/* { dg-options "-O -fschedule-insns" } */
+
+typedef unsigned char u8;
+typedef unsigned __int128 u128;
+
+static u128 u128_0;
+static u128 *p128;
+
+u128 __attribute__ ((noinline, noclone))
+foo(u8 u8_0)
+{
+ p128 = &u128_0;
+ u128_0 = u8_0;
+ u128_0 = u128_0 << 127 | u128_0 >> 1;
+ u128_0 >>= (u8)u128_0;
+ return 2 + u128_0;
+}
+
+int
+main()
+{
+ u128 x = foo(5);
+ if (p128 != &u128_0)
+ __builtin_abort();
+ if (u128_0 != ((u128)2 << 124))
+ __builtin_abort();
+ if (x != ((u128)2 << 124) + 2)
+ __builtin_abort();
+ return 0;
+}
Hello! We need earlyclobber on output operand of doubleword shift insns, since we have to prevent (partial) output matching %ecx as count argument. 2016-11-09 Uros Bizjak <ubizjak@gmail.com> PR target/78262 * config/i386/i386.md (*<shift_insn><mode>3_doubleword): Mark operand 0 as earlyclobber. testsuite/ChangeLog: 2016-11-09 Uros Bizjak <ubizjak@gmail.com> PR target/78262 * gcc.target/i386/pr78262.c: New test. Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}. Committed to mainline, will be backported to release branches. Uros.