[ConstantRange] Add support of mul in makeGuaranteedNoWrapRegion.
Summary: This is trying to add support for r334428.
Reviewers: sanjoy
Subscribers: jlebar, hiraditya, bixia, llvm-commits
Differential Revision: https://reviews.llvm.org/D48399
llvm-svn: 335646
diff --git a/llvm/lib/IR/ConstantRange.cpp b/llvm/lib/IR/ConstantRange.cpp
index 157473f..86cd24b 100644
--- a/llvm/lib/IR/ConstantRange.cpp
+++ b/llvm/lib/IR/ConstantRange.cpp
@@ -255,6 +255,64 @@
APInt::getSignedMinValue(BitWidth) + SignedMin));
}
return Result;
+ case Instruction::Mul: {
+ if (NoWrapKind == (OBO::NoSignedWrap | OBO::NoUnsignedWrap)) {
+ return SubsetIntersect(
+ makeGuaranteedNoWrapRegion(BinOp, Other, OBO::NoSignedWrap),
+ makeGuaranteedNoWrapRegion(BinOp, Other, OBO::NoUnsignedWrap));
+ }
+
+ // Equivalent to calling makeGuaranteedNoWrapRegion() on [V, V+1).
+ const bool Unsigned = NoWrapKind == OBO::NoUnsignedWrap;
+ const auto makeSingleValueRegion = [Unsigned,
+ BitWidth](APInt V) -> ConstantRange {
+ // Handle special case for 0, -1 and 1. See the last for reason why we
+ // specialize -1 and 1.
+ if (V == 0 || V.isOneValue())
+ return ConstantRange(BitWidth, true);
+
+ APInt MinValue, MaxValue;
+ if (Unsigned) {
+ MinValue = APInt::getMinValue(BitWidth);
+ MaxValue = APInt::getMaxValue(BitWidth);
+ } else {
+ MinValue = APInt::getSignedMinValue(BitWidth);
+ MaxValue = APInt::getSignedMaxValue(BitWidth);
+ }
+ // e.g. Returning [-127, 127], represented as [-127, -128).
+ if (!Unsigned && V.isAllOnesValue())
+ return ConstantRange(-MaxValue, MinValue);
+
+ APInt Lower, Upper;
+ if (!Unsigned && V.isNegative()) {
+ Lower = APIntOps::RoundingSDiv(MaxValue, V, APInt::Rounding::UP);
+ Upper = APIntOps::RoundingSDiv(MinValue, V, APInt::Rounding::DOWN);
+ } else if (Unsigned) {
+ Lower = APIntOps::RoundingUDiv(MinValue, V, APInt::Rounding::UP);
+ Upper = APIntOps::RoundingUDiv(MaxValue, V, APInt::Rounding::DOWN);
+ } else {
+ Lower = APIntOps::RoundingSDiv(MinValue, V, APInt::Rounding::UP);
+ Upper = APIntOps::RoundingSDiv(MaxValue, V, APInt::Rounding::DOWN);
+ }
+ if (Unsigned) {
+ Lower = Lower.zextOrSelf(BitWidth);
+ Upper = Upper.zextOrSelf(BitWidth);
+ } else {
+ Lower = Lower.sextOrSelf(BitWidth);
+ Upper = Upper.sextOrSelf(BitWidth);
+ }
+ // ConstantRange ctor take a half inclusive interval [Lower, Upper + 1).
+ // Upper + 1 is guanranteed not to overflow, because |divisor| > 1. 0, -1,
+ // and 1 are already handled as special cases.
+ return ConstantRange(Lower, Upper + 1);
+ };
+
+ if (Unsigned)
+ return makeSingleValueRegion(Other.getUnsignedMax());
+
+ return SubsetIntersect(makeSingleValueRegion(Other.getSignedMin()),
+ makeSingleValueRegion(Other.getSignedMax()));
+ }
}
}