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[InstCombine] safely create a constant of the right type (PR35794) 

llvm-svn: 321801
This commit is contained in:
Sanjay Patel 2018-01-04 14:31:56 +00:00
parent 7d9198b296
commit c63f9014d6
2 changed files with 20 additions and 4 deletions
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8
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
View File

@ -4082,13 +4082,13 @@ Instruction *InstCombiner::foldICmpUsingKnownBits(ICmpInst &I) {
computeUnsignedMinMaxValuesFromKnownBits(Op1Known, Op1Min, Op1Max);
}
// If Min and Max are known to be the same, then SimplifyDemandedBits
// figured out that the LHS is a constant. Constant fold this now, so that
// If Min and Max are known to be the same, then SimplifyDemandedBits figured
// out that the LHS or RHS is a constant. Constant fold this now, so that
// code below can assume that Min != Max.
if (!isa<Constant>(Op0) && Op0Min == Op0Max)
return new ICmpInst(Pred, ConstantInt::get(Op0->getType(), Op0Min), Op1);
return new ICmpInst(Pred, ConstantExpr::getIntegerValue(Ty, Op0Min), Op1);
if (!isa<Constant>(Op1) && Op1Min == Op1Max)
return new ICmpInst(Pred, Op0, ConstantInt::get(Op1->getType(), Op1Min));
return new ICmpInst(Pred, Op0, ConstantExpr::getIntegerValue(Ty, Op1Min));
// Based on the range information we know about the LHS, see if we can
// simplify this comparison. For example, (x&4) < 8 is always true.

16
llvm/test/Transforms/InstCombine/icmp.ll
View File

@ -3286,3 +3286,19 @@ define i32 @abs_preserve(i32 %x) {
%abs = select i1 %c, i32 %a, i32 %nega
ret i32 %abs
}
; Don't crash by assuming the compared values are integers.
declare void @llvm.assume(i1)
define i1 @PR35794(i32* %a) {
; CHECK-LABEL: @PR35794(
; CHECK-NEXT: [[MASKCOND:%.*]] = icmp eq i32* %a, null
; CHECK-NEXT: tail call void @llvm.assume(i1 [[MASKCOND]])
; CHECK-NEXT: ret i1 true
;
%cmp = icmp sgt i32* %a, inttoptr (i64 -1 to i32*)
%maskcond = icmp eq i32* %a, null
tail call void @llvm.assume(i1 %maskcond)
ret i1 %cmp
}