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Constant-fold certain comparisons with infinity and negative infinity.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96777 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-02-22 04:06:03 +00:00
parent 31a95c524c
commit 6b617a7213
2 changed files with 181 additions and 0 deletions
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26
lib/Analysis/InstructionSimplify.cpp
View File

@ -283,6 +283,32 @@ Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
// True if unordered.
return ConstantInt::getTrue(CFP->getContext());
}
// Check whether the constant is an infinity.
if (CFP->getValueAPF().isInfinity()) {
if (CFP->getValueAPF().isNegative()) {
switch (Pred) {
case FCmpInst::FCMP_OLT:
// No value is ordered and less than negative infinity.
return ConstantInt::getFalse(CFP->getContext());
case FCmpInst::FCMP_UGE:
// All values are unordered with or at least negative infinity.
return ConstantInt::getTrue(CFP->getContext());
default:
break;
}
} else {
switch (Pred) {
case FCmpInst::FCMP_OGT:
// No value is ordered and greater than infinity.
return ConstantInt::getFalse(CFP->getContext());
case FCmpInst::FCMP_ULE:
// All values are unordered with and at most infinity.
return ConstantInt::getTrue(CFP->getContext());
default:
break;
}
}
}
}
}

155
test/Transforms/InstCombine/fcmp-special.ll Normal file
View File

@ -0,0 +1,155 @@
; RUN: opt < %s -instcombine -S | FileCheck %s
; Infinity
; CHECK: inf0
; CHECK: ret i1 false
define i1 @inf0(double %arg) nounwind readnone {
%tmp = fcmp ogt double %arg, 0x7FF0000000000000
ret i1 %tmp
}
; CHECK: inf1
; CHECK: ret i1 true
define i1 @inf1(double %arg) nounwind readnone {
%tmp = fcmp ule double %arg, 0x7FF0000000000000
ret i1 %tmp
}
; Negative infinity
; CHECK: ninf0
; CHECK: ret i1 false
define i1 @ninf0(double %arg) nounwind readnone {
%tmp = fcmp olt double %arg, 0xFFF0000000000000
ret i1 %tmp
}
; CHECK: ninf1
; CHECK: ret i1 true
define i1 @ninf1(double %arg) nounwind readnone {
%tmp = fcmp uge double %arg, 0xFFF0000000000000
ret i1 %tmp
}
; NaNs
; CHECK: nan0
; CHECK: ret i1 false
define i1 @nan0(double %arg) nounwind readnone {
%tmp = fcmp ord double %arg, 0x7FF00000FFFFFFFF
ret i1 %tmp
}
; CHECK: nan1
; CHECK: ret i1 false
define i1 @nan1(double %arg) nounwind readnone {
%tmp = fcmp oeq double %arg, 0x7FF00000FFFFFFFF
ret i1 %tmp
}
; CHECK: nan2
; CHECK: ret i1 false
define i1 @nan2(double %arg) nounwind readnone {
%tmp = fcmp olt double %arg, 0x7FF00000FFFFFFFF
ret i1 %tmp
}
; CHECK: nan3
; CHECK: ret i1 true
define i1 @nan3(double %arg) nounwind readnone {
%tmp = fcmp uno double %arg, 0x7FF00000FFFFFFFF
ret i1 %tmp
}
; CHECK: nan4
; CHECK: ret i1 true
define i1 @nan4(double %arg) nounwind readnone {
%tmp = fcmp une double %arg, 0x7FF00000FFFFFFFF
ret i1 %tmp
}
; CHECK: nan5
; CHECK: ret i1 true
define i1 @nan5(double %arg) nounwind readnone {
%tmp = fcmp ult double %arg, 0x7FF00000FFFFFFFF
ret i1 %tmp
}
; Negative NaN.
; CHECK: nnan0
; CHECK: ret i1 false
define i1 @nnan0(double %arg) nounwind readnone {
%tmp = fcmp ord double %arg, 0xFFF00000FFFFFFFF
ret i1 %tmp
}
; CHECK: nnan1
; CHECK: ret i1 false
define i1 @nnan1(double %arg) nounwind readnone {
%tmp = fcmp oeq double %arg, 0xFFF00000FFFFFFFF
ret i1 %tmp
}
; CHECK: nnan2
; CHECK: ret i1 false
define i1 @nnan2(double %arg) nounwind readnone {
%tmp = fcmp olt double %arg, 0xFFF00000FFFFFFFF
ret i1 %tmp
}
; CHECK: nnan3
; CHECK: ret i1 true
define i1 @nnan3(double %arg) nounwind readnone {
%tmp = fcmp uno double %arg, 0xFFF00000FFFFFFFF
ret i1 %tmp
}
; CHECK: nnan4
; CHECK: ret i1 true
define i1 @nnan4(double %arg) nounwind readnone {
%tmp = fcmp une double %arg, 0xFFF00000FFFFFFFF
ret i1 %tmp
}
; CHECK: nnan5
; CHECK: ret i1 true
define i1 @nnan5(double %arg) nounwind readnone {
%tmp = fcmp ult double %arg, 0xFFF00000FFFFFFFF
ret i1 %tmp
}
; Negative zero.
; CHECK: nzero0
; CHECK: ret i1 true
define i1 @nzero0() {
%tmp = fcmp oeq double 0.0, -0.0
ret i1 %tmp
}
; CHECK: nzero1
; CHECK: ret i1 false
define i1 @nzero1() {
%tmp = fcmp ogt double 0.0, -0.0
ret i1 %tmp
}
; Misc.
; CHECK: misc0
; CHECK: %tmp = fcmp ord double %arg, 0.000000e+00
; CHECK: ret i1 %tmp
define i1 @misc0(double %arg) {
%tmp = fcmp oeq double %arg, %arg
ret i1 %tmp
}
; CHECK: misc1
; CHECK: ret i1 false
define i1 @misc1(double %arg) {
%tmp = fcmp one double %arg, %arg
ret i1 %tmp
}