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-rw-r--r--lib/Transforms/InstCombine/InstCombineCompares.cpp16
-rw-r--r--test/Transforms/InstCombine/icmp.ll10
2 files changed, 23 insertions, 3 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 999de34..7c67bf6 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1340,6 +1340,16 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
}
}
break;
+
+ case Instruction::SRem: {
+ bool TrueIfSigned;
+ if (LHSI->hasOneUse() &&
+ isSignBitCheck(ICI.getPredicate(), RHS, TrueIfSigned)) {
+ // srem has the same sign as its dividend so the divisor is irrelevant.
+ return new ICmpInst(ICI.getPredicate(), LHSI->getOperand(0), RHS);
+ }
+ break;
+ }
}
// Simplify icmp_eq and icmp_ne instructions with integer constant RHS.
@@ -1855,11 +1865,11 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
return new ICmpInst(ICmpInst::ICMP_SLT, Op0,
ConstantInt::get(CI->getContext(), CI->getValue()+1));
case ICmpInst::ICMP_UGE:
- assert(!CI->isMinValue(false)); // A >=u MIN -> TRUE
+ assert(!CI->isMinValue(false)); // A >=u MIN -> TRUE
return new ICmpInst(ICmpInst::ICMP_UGT, Op0,
ConstantInt::get(CI->getContext(), CI->getValue()-1));
case ICmpInst::ICMP_SGE:
- assert(!CI->isMinValue(true)); // A >=s MIN -> TRUE
+ assert(!CI->isMinValue(true)); // A >=s MIN -> TRUE
return new ICmpInst(ICmpInst::ICMP_SGT, Op0,
ConstantInt::get(CI->getContext(), CI->getValue()-1));
}
@@ -1913,7 +1923,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
ConstantInt::get(I.getContext(), 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.
+ // simplify this comparison. For example, (x&4) < 8 is always true.
switch (I.getPredicate()) {
default: llvm_unreachable("Unknown icmp opcode!");
case ICmpInst::ICMP_EQ: {
diff --git a/test/Transforms/InstCombine/icmp.ll b/test/Transforms/InstCombine/icmp.ll
index 3150883..c11dea5 100644
--- a/test/Transforms/InstCombine/icmp.ll
+++ b/test/Transforms/InstCombine/icmp.ll
@@ -377,3 +377,13 @@ define i1 @test38(i32 %x, i32 %y, i32 %z) {
%c = icmp ugt i32 %lhs, %rhs
ret i1 %c
}
+
+; PR9343 #7
+; CHECK: @test39
+; CHECK: ret i1 false
+define i1 @test39(i31 %X, i32 %Y) {
+ %A = zext i31 %X to i32
+ %B = srem i32 %A, %Y
+ %C = icmp slt i32 %B, 0
+ ret i1 %C
+}