diff options
| -rw-r--r-- | lib/Analysis/ValueTracking.cpp | 6 | ||||
| -rw-r--r-- | test/Transforms/InstSimplify/2011-01-18-Compare.ll | 15 |
2 files changed, 17 insertions, 4 deletions
diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 98b4489cba..5320fa0768 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -740,10 +740,10 @@ bool llvm::isKnownNonZero(Value *V, const TargetData *TD, unsigned Depth) { ComputeSignBit(Y, YKnownNonNegative, YKnownNegative, TD, Depth); // If X and Y are both non-negative (as signed values) then their sum is not - // zero. + // zero unless both X and Y are zero. if (XKnownNonNegative && YKnownNonNegative) - return false; -// return true; + if (isKnownNonZero(X, TD, Depth) || isKnownNonZero(Y, TD, Depth)) + return true; // If X and Y are both negative (as signed values) then their sum is not // zero unless both X and Y equal INT_MIN. diff --git a/test/Transforms/InstSimplify/2011-01-18-Compare.ll b/test/Transforms/InstSimplify/2011-01-18-Compare.ll index 705f354249..c905c443d2 100644 --- a/test/Transforms/InstSimplify/2011-01-18-Compare.ll +++ b/test/Transforms/InstSimplify/2011-01-18-Compare.ll @@ -61,11 +61,14 @@ define i1 @sext3() { } define i1 @add(i32 %x, i32 %y) { +; CHECK: @add %l = lshr i32 %x, 1 - %r = lshr i32 %y, 1 + %q = lshr i32 %y, 1 + %r = or i32 %q, 1 %s = add i32 %l, %r %c = icmp eq i32 %s, 0 ret i1 %c +; CHECK: ret i1 false } define i1 @add2(i8 %x, i8 %y) { @@ -78,6 +81,16 @@ define i1 @add2(i8 %x, i8 %y) { ; CHECK: ret i1 false } +define i1 @add3(i8 %x, i8 %y) { +; CHECK: @add3 + %l = zext i8 %x to i32 + %r = zext i8 %y to i32 + %s = add i32 %l, %r + %c = icmp eq i32 %s, 0 + ret i1 %c +; CHECK: ret i1 %c +} + define i1 @addpowtwo(i32 %x, i32 %y) { ; CHECK: @addpowtwo %l = lshr i32 %x, 1 |