[llvm] c7dcacf - [AMDGPU] Fixed asan failure in SIFoldOperands

[Stanislav Mekhanoshin via llvm-commits]

Author: Stanislav Mekhanoshin
Date: 2019-10-25T13:59:56-07:00
New Revision: c7dcacf16a680f6a5ef4cbe15ff9ca40f7d128b8

URL: https://github.com/llvm/llvm-project/commit/c7dcacf16a680f6a5ef4cbe15ff9ca40f7d128b8
DIFF: https://github.com/llvm/llvm-project/commit/c7dcacf16a680f6a5ef4cbe15ff9ca40f7d128b8.diff

LOG: [AMDGPU] Fixed asan failure in SIFoldOperands

Both tryFoldOMod() and tryFoldClamp() remove original instruction,
so the check MI.modifiesRegister() may use a deleted MI.

Differential Revision: https://reviews.llvm.org/D69448

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/SIFoldOperands.cpp

Removed: 
    


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diff  --git a/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp b/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
index a141a22c53fe..f24510b18665 100644
--- a/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
+++ b/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
@@ -1468,15 +1468,16 @@ bool SIFoldOperands::runOnMachineFunction(MachineFunction &MF) {
       tryFoldInst(TII, &MI);
 
       if (!TII->isFoldableCopy(MI)) {
+        // Saw an unknown clobber of m0, so we no longer know what it is.
+        if (CurrentKnownM0Val && MI.modifiesRegister(AMDGPU::M0, TRI))
+          CurrentKnownM0Val = nullptr;
+
         // TODO: Omod might be OK if there is NSZ only on the source
         // instruction, and not the omod multiply.
         if (IsIEEEMode || (!HasNSZ && !MI.getFlag(MachineInstr::FmNsz)) ||
             !tryFoldOMod(MI))
           tryFoldClamp(MI);
 
-        // Saw an unknown clobber of m0, so we no longer know what it is.
-        if (CurrentKnownM0Val && MI.modifiesRegister(AMDGPU::M0, TRI))
-          CurrentKnownM0Val = nullptr;
         continue;
       }