From cc32e81cdbb7696cd571bdb5ffe52f228f125df5 Mon Sep 17 00:00:00 2001 From: qing zhao Date: Thu, 5 Nov 2020 15:57:46 +0100 Subject: [PATCH] i386: Fix PR97715 This change fixes a bug in the i386 backend when adding -fzero-call-used-regs=all on a target that has no x87 registers. When there is no x87 registers available, we should not zero stack registers. gcc/ChangeLog: PR target/97715 * config/i386/i386.c (zero_all_st_registers): Return earlier when the FPU is disabled. gcc/testsuite/ChangeLog: PR target/97715 * gcc.target/i386/zero-scratch-regs-32.c: New test. --- gcc/config/i386/i386.c | 5 +++++ gcc/testsuite/gcc.target/i386/zero-scratch-regs-32.c | 11 +++++++++++ 2 files changed, 16 insertions(+) create mode 100644 gcc/testsuite/gcc.target/i386/zero-scratch-regs-32.c diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 6fc6228a26e..789ef727cf8 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -3640,6 +3640,11 @@ zero_all_vector_registers (HARD_REG_SET need_zeroed_hardregs) static bool zero_all_st_registers (HARD_REG_SET need_zeroed_hardregs) { + + /* If the FPU is disabled, no need to zero all st registers. */ + if (! (TARGET_80387 || TARGET_FLOAT_RETURNS_IN_80387)) + return false; + unsigned int num_of_st = 0; for (unsigned int regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) if ((STACK_REGNO_P (regno) || MMX_REGNO_P (regno)) diff --git a/gcc/testsuite/gcc.target/i386/zero-scratch-regs-32.c b/gcc/testsuite/gcc.target/i386/zero-scratch-regs-32.c new file mode 100644 index 00000000000..ca3261fe5ea --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/zero-scratch-regs-32.c @@ -0,0 +1,11 @@ +/* { dg-do compile { target *-*-linux* } } */ +/* { dg-options "-O2 -fzero-call-used-regs=all -mno-80387" } */ + +int +foo (int x) +{ + return (x + 1); +} + +/* { dg-final { scan-assembler-not "fldz" } } */ + -- 2.30.2