[llvm-commits] CVS: llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
Jeff Cohen
jeffc at jolt-lang.org
Sun Feb 27 13:08:15 PST 2005
Changes in directory llvm/lib/Transforms/Scalar:
LoopStrengthReduce.cpp updated: 1.2 -> 1.3
---
Log message:
PHI nodes were incorrectly placed when more than one GEP is reduced in a loop.
---
Diffs of the changes: (+6 -7)
LoopStrengthReduce.cpp | 13 ++++++-------
1 files changed, 6 insertions(+), 7 deletions(-)
Index: llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
diff -u llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp:1.2 llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp:1.3
--- llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp:1.2 Sun Feb 27 13:37:07 2005
+++ llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp Sun Feb 27 15:08:04 2005
@@ -99,7 +99,8 @@
// GEP.
//
// We currently only handle GEP instructions that consist of zero or more
- // constants and one instance of the canonical induction variable.
+ // constants or loop invariable expressions prior to an instance of the
+ // canonical induction variable.
unsigned indvar = 0;
std::vector<Value *> pre_op_vector;
std::vector<Value *> inc_op_vector;
@@ -208,21 +209,19 @@
if (0 == PN)
return;
- // Insert secondary PHI nodes after the canonical induction variable's PHI
- // for the strength reduced pointers that we will be creating.
- Instruction *InsertBefore = PN->getNext();
-
// FIXME: Need to use SCEV to detect GEP uses of the indvar, since indvars
// pass creates code like this, which we can't currently detect:
// %tmp.1 = sub uint 2000, %indvar
// %tmp.8 = getelementptr int* %y, uint %tmp.1
- // Strength reduce all GEPs in the Loop
+ // Strength reduce all GEPs in the Loop. Insert secondary PHI nodes for the
+ // strength reduced pointers we'll be creating after the canonical induction
+ // variable's PHI.
std::set<Instruction*> DeadInsts;
for (Value::use_iterator UI = PN->use_begin(), UE = PN->use_end();
UI != UE; ++UI)
if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*UI))
- strengthReduceGEP(GEPI, L, InsertBefore, DeadInsts);
+ strengthReduceGEP(GEPI, L, PN->getNext(), DeadInsts);
// Clean up after ourselves
if (!DeadInsts.empty()) {
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