Changes in directory llvm/lib/Transforms/Scalar:
InstructionCombining.cpp updated: 1.580 -> 1.581
---
Log message:
Implement InstCombine/vec_shuffle.ll:%test7, simplifying shuffles with
undef operands.
---
Diffs of the changes: (+23 -1)
InstructionCombining.cpp | 24 +++++++++++++++++++++++-
1 files changed, 23 insertions(+), 1 deletion(-)
Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.580
llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.581
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.580 Thu Jan 4
21:04:57 2007
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp Fri Jan 5 01:36:08 2007
@@ -8833,8 +8833,30 @@
if (isa<UndefValue>(SVI.getOperand(2)))
return ReplaceInstUsesWith(SVI, UndefValue::get(SVI.getType()));
- // TODO: If we have shuffle(x, undef, mask) and any elements of mask refer to
+ // If we have shuffle(x, undef, mask) and any elements of mask refer to
// the undef, change them to undefs.
+ if (isa<UndefValue>(SVI.getOperand(1))) {
+ // Scan to see if there are any references to the RHS. If so, replace them
+ // with undef element refs and set MadeChange to true.
+ for (unsigned i = 0, e = Mask.size(); i != e; ++i) {
+ if (Mask[i] >= e && Mask[i] != 2*e) {
+ Mask[i] = 2*e;
+ MadeChange = true;
+ }
+ }
+
+ if (MadeChange) {
+ // Remap any references to RHS to use LHS.
+ std::vector<Constant*> Elts;
+ for (unsigned i = 0, e = Mask.size(); i != e; ++i) {
+ if (Mask[i] == 2*e)
+ Elts.push_back(UndefValue::get(Type::Int32Ty));
+ else
+ Elts.push_back(ConstantInt::get(Type::Int32Ty, Mask[i]));
+ }
+ SVI.setOperand(2, ConstantPacked::get(Elts));
+ }
+ }
// Canonicalize shuffle(x ,x,mask) -> shuffle(x, undef,mask')
// Canonicalize shuffle(undef,x,mask) -> shuffle(x, undef,mask').
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