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| author | Ramana Radhakrishnan <ramana.radhakrishnan@arm.com> | 2017-12-05 16:32:55 +0000 |
|---|---|---|
| committer | Ramana Radhakrishnan <ramana@gcc.gnu.org> | 2017-12-05 16:32:55 +0000 |
| commit | 7109d224774bce3eb27e945b2e2f7ec9d7620fa9 (patch) | |
| tree | d9d3cd25b698db0b880e696ea059d924ce156c96 | |
| parent | 26c2efbc5a9baa65dfcffaf40e00955076574147 (diff) | |
| download | gcc-7109d224774bce3eb27e945b2e2f7ec9d7620fa9.zip gcc-7109d224774bce3eb27e945b2e2f7ec9d7620fa9.tar.gz gcc-7109d224774bce3eb27e945b2e2f7ec9d7620fa9.tar.bz2 | |
[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
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/config/arm/arm.md | 5 |
2 files changed, 9 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 4d58c0f..d47c575 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2017-12-05 Ramana Radhakrishnan <ramana.radhakrishnan@arm.com> + + PR target/82248 + * config/arm/arm.md (probe_stack) : Use the 'o' constraint. + 2017-12-05 Bin Cheng <bin.cheng@arm.com> * 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 545ee25..d60c5af 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" |