Give SIToFPInst preference over UIToFPInst because it is faster on platforms that are widely used.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59476 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index ba19fbf..53d3ab5 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -722,6 +722,23 @@
Incr->eraseFromParent();
}
+/// Return true if it is OK to use SIToFPInst for an inducation variable
+/// with given inital and exit values.
+static bool useSIToFPInst(ConstantFP &InitV, ConstantFP &ExitV,
+ uint64_t intIV, uint64_t intEV) {
+
+ if (InitV.getValueAPF().isNegative() || ExitV.getValueAPF().isNegative())
+ return true;
+
+ // If the iteration range can be handled by SIToFPInst then use it.
+ APInt Max = APInt::getSignedMaxValue(32);
+ if (Max.getZExtValue() > abs(intEV - intIV))
+ return true;
+
+ return false;
+}
+
+/// convertToInt - Convert APF to an integer, if possible.
static bool convertToInt(const APFloat &APF, uint64_t *intVal) {
bool isExact = false;
@@ -858,9 +875,9 @@
Incr->replaceAllUsesWith(UndefValue::get(Incr->getType()));
DeadInsts.insert(Incr);
- // Replace floating induction variable.
- if (EV->getValueAPF().isNegative()
- || InitValue->getValueAPF().isNegative()) {
+ // Replace floating induction variable. Give SIToFPInst preference over
+ // UIToFPInst because it is faster on platforms that are widely used.
+ if (useSIToFPInst(*InitValue, *EV, newInitValue, intEV)) {
SIToFPInst *Conv = new SIToFPInst(NewPHI, PH->getType(), "indvar.conv",
PH->getParent()->getFirstNonPHI());
PH->replaceAllUsesWith(Conv);