[PATCH] D65542: [PeepholeOptimizer] Don't assume bitcast def always has input

[Jinsong Ji via Phabricator via llvm-commits]

jsji updated this revision to Diff 214917.
jsji added a comment.

Fix comments and add a testcase.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D65542/new/

https://reviews.llvm.org/D65542

Files:
  llvm/lib/CodeGen/PeepholeOptimizer.cpp
  llvm/lib/Target/PowerPC/PPCInstrVSX.td
  llvm/test/CodeGen/PowerPC/bitcast-peelhole.ll


Index: llvm/test/CodeGen/PowerPC/bitcast-peelhole.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/PowerPC/bitcast-peelhole.ll
@@ -0,0 +1,13 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; REQUIRES: asserts
+; RUN: llc -mcpu=pwr9 -ppc-asm-full-reg-names -ppc-vsr-nums-as-vr \
+; RUN:   -mtriple=powerpc64le-unknown-unknown < %s | FileCheck %s
+
+define < 4 x i32> @bitCast() {
+; CHECK-LABEL: bitCast:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    xxleqv v2, v2, v2
+; CHECK-NEXT:    blr
+entry:
+  ret < 4 x i32> <i32 -1, i32 -1,i32 -1,i32 -1 >
+}
Index: llvm/lib/Target/PowerPC/PPCInstrVSX.td
===================================================================
--- llvm/lib/Target/PowerPC/PPCInstrVSX.td
+++ llvm/lib/Target/PowerPC/PPCInstrVSX.td
@@ -1314,11 +1314,8 @@
       isReMaterializable = 1 in {
     def XXLEQVOnes : XX3Form_SameOp<60, 186, (outs vsrc:$XT), (ins),
                          "xxleqv $XT, $XT, $XT", IIC_VecGeneral,
-                         [(set v4i32:$XT, (v4i32 immAllOnesV))]>;
+                         [(set v4i32:$XT, (bitconvert (v16i8 immAllOnesV)))]>;
   }
-  
-  def : Pat<(v4i32 (bitconvert (v16i8 immAllOnesV))),
-            (XXLEQVOnes)>;
 
   def XXLORC : XX3Form<60, 170,
                        (outs vsrc:$XT), (ins vsrc:$XA, vsrc:$XB),
Index: llvm/lib/CodeGen/PeepholeOptimizer.cpp
===================================================================
--- llvm/lib/CodeGen/PeepholeOptimizer.cpp
+++ llvm/lib/CodeGen/PeepholeOptimizer.cpp
@@ -1853,6 +1853,11 @@
     SrcIdx = OpIdx;
   }
 
+  // In some rare case, Def has no input, SrcIdx is out of bound,
+  // getOperand(SrcIdx) will fail below.
+  if (SrcIdx >= Def->getNumOperands())
+    return ValueTrackerResult();
+
   // Stop when any user of the bitcast is a SUBREG_TO_REG, replacing with a COPY
   // will break the assumed guarantees for the upper bits.
   for (const MachineInstr &UseMI : MRI.use_nodbg_instructions(DefOp.getReg())) {


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