From 76eafcc395d2bcd4147cb1ba1a8aff321571402f Mon Sep 17 00:00:00 2001 From: Roger Sayle Date: Tue, 4 Aug 2020 16:56:06 +0100 Subject: [PATCH] Test case for PR rtl-optimization/60473 PR rtl-optimization/60473 is code quality regression that has been cured by improvements to register allocation. For the function in the test case, GCC 4.4, 4.5 and 4.6 generated very poor code requiring two mov instructions, and GCC 4.7 and 4.8 (when the PR was filed) produced better but still poor code with one mov instruction. Since GCC 4.9 (including current mainline), it generates optimal code with no mov instructions, matching what used to be generated in GCC 4.1. 2020-08-04 Roger Sayle gcc/testsuite/ChangeLog PR rtl-optimization/60473 * gcc.target/i386/pr60473.c: New test. --- gcc/testsuite/gcc.target/i386/pr60473.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) create mode 100644 gcc/testsuite/gcc.target/i386/pr60473.c diff --git a/gcc/testsuite/gcc.target/i386/pr60473.c b/gcc/testsuite/gcc.target/i386/pr60473.c new file mode 100644 index 00000000000..d81962e7b67 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr60473.c @@ -0,0 +1,12 @@ +/* PR rtl-optimization/60473 */ +/* { dg-do compile { target { ! ia32 } } } */ +/* { dg-options "-O2" } */ + +unsigned long long foo() +{ + unsigned long long h,l; + asm volatile ("rdtsc": "=a" (l), "=d" (h)); + return l | (h << 32); +} + +/* { dg-final { scan-assembler-not "mov" } } */ -- 2.30.2