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
This commit is contained in:
Devang Patel 2008-11-18 00:40:02 +00:00
parent 2d093f3560
commit 13877bf6c2
2 changed files with 55 additions and 3 deletions

View File

@ -722,6 +722,23 @@ void IndVarSimplify::OptimizeCanonicalIVType(Loop *L) {
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 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PH,
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);

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@ -0,0 +1,35 @@
; RUN: llvm-as < %s | opt -indvars | llvm-dis | grep icmp | count 2
; RUN: llvm-as < %s | opt -indvars | llvm-dis | grep sitofp | count 1
; RUN: llvm-as < %s | opt -indvars | llvm-dis | grep uitofp | count 1
define void @bar() nounwind {
entry:
br label %bb
bb: ; preds = %bb, %entry
%x.0.reg2mem.0 = phi double [ 0.000000e+00, %entry ], [ %1, %bb ] ; <double> [#uses=2]
%0 = tail call i32 @foo(double %x.0.reg2mem.0) nounwind ; <i32> [#uses=0]
%1 = add double %x.0.reg2mem.0, 1.0e+0 ; <double> [#uses=2]
%2 = fcmp olt double %1, 2147483646.0e+0 ; <i1> [#uses=1]
br i1 %2, label %bb, label %return
return: ; preds = %bb
ret void
}
define void @bar1() nounwind {
entry:
br label %bb
bb: ; preds = %bb, %entry
%x.0.reg2mem.0 = phi double [ 0.000000e+00, %entry ], [ %1, %bb ] ; <double> [#uses=2]
%0 = tail call i32 @foo(double %x.0.reg2mem.0) nounwind ; <i32> [#uses=0]
%1 = add double %x.0.reg2mem.0, 1.0e+0 ; <double> [#uses=2]
%2 = fcmp olt double %1, 2147483647.0e+0 ; <i1> [#uses=1]
br i1 %2, label %bb, label %return
return: ; preds = %bb
ret void
}
declare i32 @foo(double)