From 7109d224774bce3eb27e945b2e2f7ec9d7620fa9 Mon Sep 17 00:00:00 2001 From: Ramana Radhakrishnan Date: Tue, 5 Dec 2017 16:32:55 +0000 Subject: [PATCH] [Patch ARM] Fix probe_stack constraint. The probe_stack pattern uses r0 as a fixed register. This can cause issues if we have auto-increment instructions coming out that have r0 as the base register. Tested with a bootstrap and regression run. richi reports that the original issue was fixed in the run. I did consider whether probe_stack_range was affected but it all comes back to probe_stack pattern so I think we are ok. I don't have a testcase that seems to provoke this but it seems to be default on most distributions so I'm expecting the testcoverage to come from there. Applied. Ramana PR target/82248 * config/arm/arm.md (probe_stack) : Use the 'o' constraint. From-SVN: r255428 --- gcc/ChangeLog | 5 +++++ gcc/config/arm/arm.md | 5 ++++- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 4d58c0f9aec..d47c575763a 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2017-12-05 Ramana Radhakrishnan + + PR target/82248 + * config/arm/arm.md (probe_stack) : Use the 'o' constraint. + 2017-12-05 Bin Cheng * tree-ssa-dce.c (simple_dce_from_worklist): Move and rename from diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md index 545ee257699..d60c5af551c 100644 --- a/gcc/config/arm/arm.md +++ b/gcc/config/arm/arm.md @@ -8612,8 +8612,11 @@ (set_attr "type" "block")] ) +;; Since we hard code r0 here use the 'o' constraint to prevent +;; provoking undefined behaviour in the hardware with putting out +;; auto-increment operations with potentially r0 as the base register. (define_insn "probe_stack" - [(set (match_operand:SI 0 "memory_operand" "=m") + [(set (match_operand:SI 0 "memory_operand" "=o") (unspec:SI [(const_int 0)] UNSPEC_PROBE_STACK))] "TARGET_32BIT" "str%?\\tr0, %0" -- 2.30.2