From 6073d0028debf7cbd80dc0678402cbe2c6ea652d Mon Sep 17 00:00:00 2001 From: Segher Boessenkool Date: Wed, 20 Sep 2017 23:48:31 +0200 Subject: [PATCH] rs6000: Don't touch below the stack pointer (PR77687) With the 32-bit SVR4 ABI we don't have a red zone, so we have to restore the callee-saved registers before we restore the stack pointer. The previous fix for this PR failed in two ways, for huge frames: first, we use a negative offset from r11 in that case, so the (mem:BLK 11) access does no good; second, sched does not handle accesses to mem:BLK correctly in this case (does not make dependencies). This patch fixes it by doing a store to (mem:BLK (scratch)) instead. This means no unrelated (not to stack) loads/stores can be moved over the stack restore either, but so be it. PR target/77687 * config/rs6000/rs6000.md (stack_restore_tie): Store to a scratch address instead of to r1 and r11. gcc/testsuite/ PR target/77687 * gcc.target/powerpc/pr77687.c: New testcase. From-SVN: r253033 --- gcc/ChangeLog | 6 ++++++ gcc/config/rs6000/rs6000.md | 6 ++---- gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/gcc.target/powerpc/pr77687.c | 20 ++++++++++++++++++++ 4 files changed, 33 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/gcc.target/powerpc/pr77687.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 1bbb3bf6eb4..371b7902f37 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2017-09-20 Segher Boessenkool + + PR target/77687 + * config/rs6000/rs6000.md (stack_restore_tie): Store to a scratch + address instead of to r1 and r11. + 2017-09-20 Sebastian Peryt * config.gcc: Support "knm". diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md index 7f176283872..13ba7438124 100644 --- a/gcc/config/rs6000/rs6000.md +++ b/gcc/config/rs6000/rs6000.md @@ -13161,14 +13161,12 @@ ; Some 32-bit ABIs do not have a red zone, so the stack deallocation has to ; stay behind all restores from the stack, it cannot be reordered to before -; one. See PR77687. This insn is an add or mr, and a stack_tie on the -; operands of that. +; one. See PR77687. This insn is an add or mr, and a memory clobber. (define_insn "stack_restore_tie" [(set (match_operand:SI 0 "gpc_reg_operand" "=r,r") (plus:SI (match_operand:SI 1 "gpc_reg_operand" "r,r") (match_operand:SI 2 "reg_or_cint_operand" "O,rI"))) - (set (mem:BLK (match_dup 0)) (const_int 0)) - (set (mem:BLK (match_dup 1)) (const_int 0))] + (set (mem:BLK (scratch)) (const_int 0))] "TARGET_32BIT" "@ mr %0,%1 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 801adf0def9..eebb33d0b96 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2017-09-19 Segher Boessenkool + + PR target/77687 + * gcc.target/powerpc/pr77687.c: New testcase. + 2017-09-20 Jakub Jelinek P0409R2 - allow lambda capture [=, this] diff --git a/gcc/testsuite/gcc.target/powerpc/pr77687.c b/gcc/testsuite/gcc.target/powerpc/pr77687.c new file mode 100644 index 00000000000..95b27ae99e4 --- /dev/null +++ b/gcc/testsuite/gcc.target/powerpc/pr77687.c @@ -0,0 +1,20 @@ +/* { dg-options "-std=gnu99 -O2" } */ +/* { dg-final { scan-assembler-not {\mmr r?1,r?11\M.*11.*\mblr\M} } } */ + +/* PR77687: We used to do stack accesses (via r11) after restoring r1. */ + +void g(int, char *); +const char * dum = "hello"; + +void f(int x) +{ + char big[200000]; + start: + g(x, big); + g(x, big); + register void *p asm("r11") = &&start; + asm("" : : "r"(p)); + asm("" : : :"r28"); + asm("" : : :"r29"); + asm("" : : :"r30"); +} -- 2.30.2