[PATCH] D58049: [InstCombine] Fix matchRotate bug when one operand is a ConstantExpr shift

[Andrew Scheidecker via Phabricator via llvm-commits]

AndrewScheidecker updated this revision to Diff 186265.
AndrewScheidecker added a comment.

Good point that we can discard the ConstantExpr case entirely.


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D58049/new/

https://reviews.llvm.org/D58049

Files:
  lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  test/Transforms/InstCombine/rotate.ll


Index: test/Transforms/InstCombine/rotate.ll
===================================================================
--- test/Transforms/InstCombine/rotate.ll
+++ test/Transforms/InstCombine/rotate.ll
@@ -689,3 +689,17 @@
   ret i24 %r
 }
 
+; Test that the transform doesn't crash when there's an "or" with a ConstantExpr operand.
+
+ at external_global = external global i8
+
+define i32 @rotl_constant_expr(i32 %shamt) {
+; CHECK-LABEL: @rotl_constant_expr(
+; CHECK-NEXT:    [[SHR:%.*]] = lshr i32 ptrtoint (i8* @external_global to i32), [[SHAMT:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = or i32 [[SHR]], shl (i32 ptrtoint (i8* @external_global to i32), i32 11)
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shr = lshr i32 ptrtoint (i8* @external_global to i32), %shamt
+  %r = or i32 %shr, shl (i32 ptrtoint (i8* @external_global to i32), i32 11)
+  ret i32 %r
+}
\ No newline at end of file
Index: lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1819,14 +1819,18 @@
 
   // First, find an or'd pair of opposite shifts with the same shifted operand:
   // or (lshr ShVal, ShAmt0), (shl ShVal, ShAmt1)
-  Value *Or0 = Or.getOperand(0), *Or1 = Or.getOperand(1);
+  BinaryOperator *Or0, *Or1;
+  if (!match(Or.getOperand(0), m_BinOp(Or0)) ||
+      !match(Or.getOperand(1), m_BinOp(Or1)))
+    return nullptr;
+
   Value *ShVal, *ShAmt0, *ShAmt1;
   if (!match(Or0, m_OneUse(m_LogicalShift(m_Value(ShVal), m_Value(ShAmt0)))) ||
       !match(Or1, m_OneUse(m_LogicalShift(m_Specific(ShVal), m_Value(ShAmt1)))))
     return nullptr;
 
-  auto ShiftOpcode0 = cast<BinaryOperator>(Or0)->getOpcode();
-  auto ShiftOpcode1 = cast<BinaryOperator>(Or1)->getOpcode();
+  BinaryOperator::BinaryOps ShiftOpcode0 = Or0->getOpcode();
+  BinaryOperator::BinaryOps ShiftOpcode1 = Or1->getOpcode();
   if (ShiftOpcode0 == ShiftOpcode1)
     return nullptr;
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D58049.186265.patch
Type: text/x-patch
Size: 2009 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20190211/1d1a7cbe/attachment.bin>