[PATCH] D90142: [PowerPC] Fix a crash in POWER 9 setb peephole

[Qiu Chaofan via Phabricator via llvm-commits]

qiucf created this revision.
qiucf added reviewers: jsji, nemanjai, PowerPC, steven.zhang, jedilyn.
Herald added subscribers: llvm-commits, shchenz, kbarton, hiraditya.
Herald added a project: LLVM.
qiucf requested review of this revision.

Variable `InnerIsSel` references `FalseRes`, while `FalseRes` might be `zext`/`sext`. So `InnerIsSel` should reference `SetOrSelCC`, otherwise a crash will happen.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D90142

Files:
  llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
  llvm/test/CodeGen/PowerPC/ppc64-P9-setb.ll


Index: llvm/test/CodeGen/PowerPC/ppc64-P9-setb.ll
===================================================================
--- llvm/test/CodeGen/PowerPC/ppc64-P9-setb.ll
+++ llvm/test/CodeGen/PowerPC/ppc64-P9-setb.ll
@@ -1328,3 +1328,18 @@
 ; CHECK: isel
 ; CHECK: blr
 }
+
+; Verify this case doesn't crash
+define void @setbn4(i128 %0, i32* %sel.out) {
+entry:
+; CHECK-LABEL: setbn4:
+; CHECK-NOT: {{\<setb\>}}
+; CHECK: isel
+; CHECK: blr
+  %c1 = icmp ult i128 %0, 5192296858534827628530496329220096
+  %c2 = icmp ugt i128 %0, 5192296858534827628530496329220096
+  %ext = zext i1 %c2 to i32
+  %sel = select i1 %c1, i32 -1, i32 %ext
+  store i32 %sel, i32* %sel.out, align 4
+  ret void
+}
Index: llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -4227,8 +4227,10 @@
        (FalseRes.getOpcode() != ISD::SELECT_CC || CC != ISD::SETEQ)))
     return false;
 
-  bool InnerIsSel = FalseRes.getOpcode() == ISD::SELECT_CC;
-  SDValue SetOrSelCC = InnerIsSel ? FalseRes : FalseRes.getOperand(0);
+  SDValue SetOrSelCC = FalseRes.getOpcode() == ISD::SELECT_CC
+                           ? FalseRes
+                           : FalseRes.getOperand(0);
+  bool InnerIsSel = SetOrSelCC.getOpcode() == ISD::SELECT_CC;
   if (SetOrSelCC.getOpcode() != ISD::SETCC &&
       SetOrSelCC.getOpcode() != ISD::SELECT_CC)
     return false;


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