[Hexagon] Fix reuse bug in Vector Loop Carried Reuse pass
The Hexagon Vector Loop Carried Reuse pass was allowing reuse between
two shufflevectors with different masks. The reason is that the masks
are not instruction objects, so the code that checks each operand
just skipped over the operands.
This patch fixes the bug by checking if the operands are the same
when they are not instruction objects. If the objects are not the
same, then the code assumes that reuse cannot occur.
Differential Revision: https://reviews.llvm.org/D60019
llvm-svn: 358292
diff --git a/llvm/lib/Target/Hexagon/HexagonVectorLoopCarriedReuse.cpp b/llvm/lib/Target/Hexagon/HexagonVectorLoopCarriedReuse.cpp
index b3ef3e4..7236dd2 100644
--- a/llvm/lib/Target/Hexagon/HexagonVectorLoopCarriedReuse.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonVectorLoopCarriedReuse.cpp
@@ -429,11 +429,18 @@
for (int OpNo = 0; OpNo < NumOperands; ++OpNo) {
Value *Op = I->getOperand(OpNo);
- Instruction *OpInst = dyn_cast<Instruction>(Op);
- if (!OpInst)
- continue;
-
Value *BEOp = BEUser->getOperand(OpNo);
+
+ Instruction *OpInst = dyn_cast<Instruction>(Op);
+ if (!OpInst) {
+ if (Op == BEOp)
+ continue;
+ // Do not allow reuse to occur when the operands may be different
+ // values.
+ BEUser = nullptr;
+ break;
+ }
+
Instruction *BEOpInst = dyn_cast<Instruction>(BEOp);
if (!isDepChainBtwn(OpInst, BEOpInst, Iters)) {
