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| author | Craig Topper <craig.topper@intel.com> | 2019-02-19 22:37:00 +0000 |
|---|---|---|
| committer | Craig Topper <craig.topper@intel.com> | 2019-02-19 22:37:00 +0000 |
| commit | 8eade092497e17ad1cfbb1a7c3d9156686b229cc (patch) | |
| tree | eec7c65ac36e8cea9fdfec1090f11b48595d25b8 /llvm/lib | |
| parent | b6bc11d4067df37af30cddddc7f1ffd42391b901 (diff) | |
| download | bcm5719-llvm-8eade092497e17ad1cfbb1a7c3d9156686b229cc.tar.gz bcm5719-llvm-8eade092497e17ad1cfbb1a7c3d9156686b229cc.zip | |
[X86] Mark FP32_TO_INT16_IN_MEM/FP32_TO_INT32_IN_MEM/FP32_TO_INT64_IN_MEM as clobbering EFLAGS to prevent mis-scheduling during conversion from SelectionDAG to MIR.
After r354178, these instruction expand to a sequence that uses an OR instruction. That OR clobbers EFLAGS so we need to state that to avoid accidentally using the clobbered flags.
Our tests show the bug, but I didn't notice because the SETcc instructions didn't move after r354178 since it used to be safe to do the fp->int conversion first.
We should probably convert this whole sequence to SelectionDAG instead of a custom inserter to avoid mistakes like this.
Fixes PR40779
llvm-svn: 354395
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/X86/X86InstrFPStack.td | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/llvm/lib/Target/X86/X86InstrFPStack.td b/llvm/lib/Target/X86/X86InstrFPStack.td index 753e33b5f99..f46aae17515 100644 --- a/llvm/lib/Target/X86/X86InstrFPStack.td +++ b/llvm/lib/Target/X86/X86InstrFPStack.td @@ -113,7 +113,9 @@ def fpimmneg1 : FPImmLeaf<fAny, [{ }]>; // Some 'special' instructions - expanded after instruction selection. -let usesCustomInserter = 1, hasNoSchedulingInfo = 1 in { +// Clobbers EFLAGS due to OR instruction used internally. +// FIXME: Can we model this in SelectionDAG? +let usesCustomInserter = 1, hasNoSchedulingInfo = 1, Defs = [EFLAGS] in { def FP32_TO_INT16_IN_MEM : PseudoI<(outs), (ins i16mem:$dst, RFP32:$src), [(X86fp_to_i16mem RFP32:$src, addr:$dst)]>; def FP32_TO_INT32_IN_MEM : PseudoI<(outs), (ins i32mem:$dst, RFP32:$src), |
