Fix LSR's ExtractImmediate and ExtractSymbol to avoid calling
ScalarEvolution::getAddExpr, which can be pretty expensive, when nothing
has changed, which is pretty common.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111042 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index f7b22a0..a040e8a 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -505,12 +505,14 @@
} else if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
SmallVector<const SCEV *, 8> NewOps(Add->op_begin(), Add->op_end());
int64_t Result = ExtractImmediate(NewOps.front(), SE);
- S = SE.getAddExpr(NewOps);
+ if (Result != 0)
+ S = SE.getAddExpr(NewOps);
return Result;
} else if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
SmallVector<const SCEV *, 8> NewOps(AR->op_begin(), AR->op_end());
int64_t Result = ExtractImmediate(NewOps.front(), SE);
- S = SE.getAddRecExpr(NewOps, AR->getLoop());
+ if (Result != 0)
+ S = SE.getAddRecExpr(NewOps, AR->getLoop());
return Result;
}
return 0;
@@ -528,12 +530,14 @@
} else if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
SmallVector<const SCEV *, 8> NewOps(Add->op_begin(), Add->op_end());
GlobalValue *Result = ExtractSymbol(NewOps.back(), SE);
- S = SE.getAddExpr(NewOps);
+ if (Result)
+ S = SE.getAddExpr(NewOps);
return Result;
} else if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
SmallVector<const SCEV *, 8> NewOps(AR->op_begin(), AR->op_end());
GlobalValue *Result = ExtractSymbol(NewOps.front(), SE);
- S = SE.getAddRecExpr(NewOps, AR->getLoop());
+ if (Result)
+ S = SE.getAddRecExpr(NewOps, AR->getLoop());
return Result;
}
return 0;