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authorDinesh Dwivedi <dinesh.d@samsung.com>2014-05-15 06:01:33 +0000
committerDinesh Dwivedi <dinesh.d@samsung.com>2014-05-15 06:01:33 +0000
commitd10a54f07fac76add4be5f3756a6121d38484938 (patch)
treea3dabb1172dd3ecc1d12c182b01824d91f6d8979
parentaf5e67a79b49c1d4f64d571e9d3a5648398438b6 (diff)
Added inst combine transforms for single bit tests from Chris's note
if ((x & C) == 0) x |= C becomes x |= C if ((x & C) != 0) x ^= C becomes x &= ~C if ((x & C) == 0) x ^= C becomes x |= C if ((x & C) != 0) x &= ~C becomes x &= ~C if ((x & C) == 0) x &= ~C becomes nothing Z3 Verifications code for above transform http://rise4fun.com/Z3/Pmsh Differential Revision: http://reviews.llvm.org/D3717 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208848 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r--lib/Transforms/InstCombine/InstCombineSelect.cpp42
-rw-r--r--test/Transforms/InstCombine/select.ll54
2 files changed, 91 insertions, 5 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 795e645840c..50b5b3740f1 100644
--- a/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -365,7 +365,15 @@ static Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
/// 1. The icmp predicate is inverted
/// 2. The select operands are reversed
/// 3. The magnitude of C2 and C1 are flipped
-static Value *foldSelectICmpAndOr(const SelectInst &SI, Value *TrueVal,
+///
+/// This also tries to turn
+/// --- Single bit tests:
+/// if ((x & C) == 0) x |= C to x |= C
+/// if ((x & C) != 0) x ^= C to x &= ~C
+/// if ((x & C) == 0) x ^= C to x |= C
+/// if ((x & C) != 0) x &= ~C to x &= ~C
+/// if ((x & C) == 0) x &= ~C to nothing
+static Value *foldSelectICmpAndOr(SelectInst &SI, Value *TrueVal,
Value *FalseVal,
InstCombiner::BuilderTy *Builder) {
const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition());
@@ -384,10 +392,34 @@ static Value *foldSelectICmpAndOr(const SelectInst &SI, Value *TrueVal,
return nullptr;
const APInt *C2;
- bool OrOnTrueVal = false;
- bool OrOnFalseVal = match(FalseVal, m_Or(m_Specific(TrueVal), m_Power2(C2)));
- if (!OrOnFalseVal)
- OrOnTrueVal = match(TrueVal, m_Or(m_Specific(FalseVal), m_Power2(C2)));
+
+ // if ((x & C) != 0) x ^= C becomes x &= ~C
+ if (match(FalseVal, m_Xor(m_Specific(TrueVal), m_APInt(C2))) && C1 == C2) {
+ return Builder->CreateAnd(TrueVal, ~(*C1));
+ }
+
+ // if ((x & C) == 0) x ^= C becomes x |= C
+ if (match(TrueVal, m_Xor(m_Specific(FalseVal), m_APInt(C2))) && C1 == C2) {
+ return Builder->CreateOr(FalseVal, *C1);
+ }
+
+ // if ((x & C) != 0) x &= ~C becomes x &= ~C
+ // if ((x & C) == 0) x &= ~C becomes nothing
+ if ((match(FalseVal, m_And(m_Specific(TrueVal), m_APInt(C2))) ||
+ match(TrueVal, m_And(m_Specific(FalseVal), m_APInt(C2)))) &&
+ *C1 == ~(*C2)) {
+ return FalseVal;
+ }
+
+ bool OrOnFalseVal = false;
+ bool OrOnTrueVal = match(TrueVal, m_Or(m_Specific(FalseVal), m_Power2(C2)));
+
+ // if ((x & C) == 0) x |= C becomes x |= C
+ if (OrOnTrueVal && C1 == C2)
+ return TrueVal;
+
+ if (!OrOnTrueVal)
+ OrOnFalseVal = match(FalseVal, m_Or(m_Specific(TrueVal), m_Power2(C2)));
if (!OrOnFalseVal && !OrOnTrueVal)
return nullptr;
diff --git a/test/Transforms/InstCombine/select.ll b/test/Transforms/InstCombine/select.ll
index 1458bde8212..1f8b38f5642 100644
--- a/test/Transforms/InstCombine/select.ll
+++ b/test/Transforms/InstCombine/select.ll
@@ -996,6 +996,60 @@ define <2 x i32> @select_icmp_eq_and_1_0_or_vector_of_2s(i32 %x, <2 x i32> %y) {
ret <2 x i32> %select
}
+; CHECK-LABEL: @select_icmp_and_8_eq_0_or_8(
+; CHECK-NEXT: [[OR:%[a-z0-9]+]] = or i32 %x, 8
+; CHECK-NEXT: ret i32 [[OR]]
+define i32 @select_icmp_and_8_eq_0_or_8(i32 %x) {
+ %and = and i32 %x, 8
+ %cmp = icmp eq i32 %and, 0
+ %or = or i32 %x, 8
+ %or.x = select i1 %cmp, i32 %or, i32 %x
+ ret i32 %or.x
+}
+
+; CHECK-LABEL: @select_icmp_and_8_ne_0_xor_8(
+; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 %x, -9
+; CHECK-NEXT: ret i32 [[AND]]
+define i32 @select_icmp_and_8_ne_0_xor_8(i32 %x) {
+ %and = and i32 %x, 8
+ %cmp = icmp eq i32 %and, 0
+ %xor = xor i32 %x, 8
+ %x.xor = select i1 %cmp, i32 %x, i32 %xor
+ ret i32 %x.xor
+}
+
+; CHECK-LABEL: @select_icmp_and_8_eq_0_xor_8(
+; CHECK-NEXT: [[OR:%[a-z0-9]+]] = or i32 %x, 8
+; CHECK-NEXT: ret i32 [[OR]]
+define i32 @select_icmp_and_8_eq_0_xor_8(i32 %x) {
+ %and = and i32 %x, 8
+ %cmp = icmp eq i32 %and, 0
+ %xor = xor i32 %x, 8
+ %xor.x = select i1 %cmp, i32 %xor, i32 %x
+ ret i32 %xor.x
+}
+
+; CHECK-LABEL: @select_icmp_and_8_ne_0_and_not_8(
+; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 %x, -9
+; CHECK-NEXT: ret i32 [[AND]]
+define i32 @select_icmp_and_8_ne_0_and_not_8(i32 %x) {
+ %and = and i32 %x, 8
+ %cmp = icmp eq i32 %and, 0
+ %and1 = and i32 %x, -9
+ %x.and1 = select i1 %cmp, i32 %x, i32 %and1
+ ret i32 %x.and1
+}
+
+; CHECK-LABEL: @select_icmp_and_8_eq_0_and_not_8(
+; CHECK-NEXT: ret i32 %x
+define i32 @select_icmp_and_8_eq_0_and_not_8(i32 %x) {
+ %and = and i32 %x, 8
+ %cmp = icmp eq i32 %and, 0
+ %and1 = and i32 %x, -9
+ %and1.x = select i1 %cmp, i32 %and1, i32 %x
+ ret i32 %and1.x
+}
+
define i32 @test65(i64 %x) {
%1 = and i64 %x, 16
%2 = icmp ne i64 %1, 0