[PATCH] D38100: [InstCombine] Teach getDemandedBitsLHSMask to handle constant splat vectors
Craig Topper via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Wed Sep 20 14:31:24 PDT 2017
craig.topper created this revision.
This replaces a ConstantInt dyn_cast with m_APInt
https://reviews.llvm.org/D38100
Files:
lib/Transforms/InstCombine/InstCombineCompares.cpp
test/Transforms/InstCombine/icmp.ll
Index: test/Transforms/InstCombine/icmp.ll
===================================================================
--- test/Transforms/InstCombine/icmp.ll
+++ test/Transforms/InstCombine/icmp.ll
@@ -1163,11 +1163,10 @@
ret <2 x i1> %cmp
}
-; FIXME: Vector constant for the 'and' should use less bits.
define <2 x i1> @test67vec2(<2 x i32> %x) {
; CHECK-LABEL: @test67vec2(
-; CHECK-NEXT: [[AND:%.*]] = and <2 x i32> %x, <i32 127, i32 127>
-; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i32> [[AND]], <i32 31, i32 31>
+; CHECK-NEXT: [[AND:%.*]] = and <2 x i32> [[X:%.*]], <i32 96, i32 96>
+; CHECK-NEXT: [[CMP:%.*]] = icmp ne <2 x i32> [[AND]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%and = and <2 x i32> %x, <i32 127, i32 127>
Index: lib/Transforms/InstCombine/InstCombineCompares.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -3926,24 +3926,24 @@
if (isSignCheck)
return APInt::getSignMask(BitWidth);
- ConstantInt *CI = dyn_cast<ConstantInt>(I.getOperand(1));
- if (!CI) return APInt::getAllOnesValue(BitWidth);
- const APInt &RHS = CI->getValue();
+ const APInt *RHS;
+ if (!match(I.getOperand(1), m_APInt(RHS)))
+ return APInt::getAllOnesValue(BitWidth);
switch (I.getPredicate()) {
// For a UGT comparison, we don't care about any bits that
// correspond to the trailing ones of the comparand. The value of these
// bits doesn't impact the outcome of the comparison, because any value
// greater than the RHS must differ in a bit higher than these due to carry.
case ICmpInst::ICMP_UGT: {
- unsigned trailingOnes = RHS.countTrailingOnes();
+ unsigned trailingOnes = RHS->countTrailingOnes();
return APInt::getBitsSetFrom(BitWidth, trailingOnes);
}
// Similarly, for a ULT comparison, we don't care about the trailing zeros.
// Any value less than the RHS must differ in a higher bit because of carries.
case ICmpInst::ICMP_ULT: {
- unsigned trailingZeros = RHS.countTrailingZeros();
+ unsigned trailingZeros = RHS->countTrailingZeros();
return APInt::getBitsSetFrom(BitWidth, trailingZeros);
}
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