[llvm] r281663 - [InstCombine] allow icmp (shr/shl) folds for vectors
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Thu Sep 15 14:35:31 PDT 2016
Author: spatel
Date: Thu Sep 15 16:35:30 2016
New Revision: 281663
URL: http://llvm.org/viewvc/llvm-project?rev=281663&view=rev
Log:
[InstCombine] allow icmp (shr/shl) folds for vectors
These 2 helper functions were already using APInt internally, so just
change the API and caller to allow folds for splats. The scalar
regression tests look quite thorough, so I just added a couple of
tests to prove that vectors are handled too.
These folds should be grouped with the other cmp+shift folds though.
That can be an NFC follow-up.
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h
llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll
llvm/trunk/test/Transforms/InstCombine/icmp.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=281663&r1=281662&r2=281663&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Thu Sep 15 16:35:30 2016
@@ -1177,8 +1177,8 @@ Instruction *InstCombiner::foldICmpAddOp
/// (icmp eq/ne A, Log2(const2/const1)) ->
/// (icmp eq/ne A, Log2(const2) - Log2(const1)).
Instruction *InstCombiner::foldICmpCstShrConst(ICmpInst &I, Value *Op, Value *A,
- ConstantInt *CI1,
- ConstantInt *CI2) {
+ const APInt &AP1,
+ const APInt &AP2) {
assert(I.isEquality() && "Cannot fold icmp gt/lt");
auto getICmp = [&I](CmpInst::Predicate Pred, Value *LHS, Value *RHS) {
@@ -1187,9 +1187,6 @@ Instruction *InstCombiner::foldICmpCstSh
return new ICmpInst(Pred, LHS, RHS);
};
- const APInt &AP1 = CI1->getValue();
- const APInt &AP2 = CI2->getValue();
-
// Don't bother doing any work for cases which InstSimplify handles.
if (AP2 == 0)
return nullptr;
@@ -1238,8 +1235,8 @@ Instruction *InstCombiner::foldICmpCstSh
/// Handle "(icmp eq/ne (shl const2, A), const1)" ->
/// (icmp eq/ne A, TrailingZeros(const1) - TrailingZeros(const2)).
Instruction *InstCombiner::foldICmpCstShlConst(ICmpInst &I, Value *Op, Value *A,
- ConstantInt *CI1,
- ConstantInt *CI2) {
+ const APInt &AP1,
+ const APInt &AP2) {
assert(I.isEquality() && "Cannot fold icmp gt/lt");
auto getICmp = [&I](CmpInst::Predicate Pred, Value *LHS, Value *RHS) {
@@ -1248,9 +1245,6 @@ Instruction *InstCombiner::foldICmpCstSh
return new ICmpInst(Pred, LHS, RHS);
};
- const APInt &AP1 = CI1->getValue();
- const APInt &AP2 = CI2->getValue();
-
// Don't bother doing any work for cases which InstSimplify handles.
if (AP2 == 0)
return nullptr;
@@ -1258,8 +1252,9 @@ Instruction *InstCombiner::foldICmpCstSh
unsigned AP2TrailingZeros = AP2.countTrailingZeros();
if (!AP1 && AP2TrailingZeros != 0)
- return getICmp(I.ICMP_UGE, A,
- ConstantInt::get(A->getType(), AP2.getBitWidth() - AP2TrailingZeros));
+ return getICmp(
+ I.ICMP_UGE, A,
+ ConstantInt::get(A->getType(), AP2.getBitWidth() - AP2TrailingZeros));
if (AP1 == AP2)
return getICmp(I.ICMP_EQ, A, ConstantInt::getNullValue(A->getType()));
@@ -1408,26 +1403,26 @@ Instruction *InstCombiner::foldICmpWithC
}
}
- // FIXME: Use m_APInt to allow folds for splat constants.
- ConstantInt *CI = dyn_cast<ConstantInt>(Cmp.getOperand(1));
- if (!CI)
- return nullptr;
-
if (Cmp.isEquality()) {
- ConstantInt *CI2;
- if (match(X, m_AShr(m_ConstantInt(CI2), m_Value(A))) ||
- match(X, m_LShr(m_ConstantInt(CI2), m_Value(A)))) {
+ const APInt *C2;
+ if (match(X, m_AShr(m_APInt(C2), m_Value(A))) ||
+ match(X, m_LShr(m_APInt(C2), m_Value(A)))) {
// (icmp eq/ne (ashr/lshr const2, A), const1)
- if (Instruction *Inst = foldICmpCstShrConst(Cmp, X, A, CI, CI2))
+ if (Instruction *Inst = foldICmpCstShrConst(Cmp, X, A, *C, *C2))
return Inst;
}
- if (match(X, m_Shl(m_ConstantInt(CI2), m_Value(A)))) {
+ if (match(X, m_Shl(m_APInt(C2), m_Value(A)))) {
// (icmp eq/ne (shl const2, A), const1)
- if (Instruction *Inst = foldICmpCstShlConst(Cmp, X, A, CI, CI2))
+ if (Instruction *Inst = foldICmpCstShlConst(Cmp, X, A, *C, *C2))
return Inst;
}
}
+ // FIXME: Use m_APInt to allow folds for splat constants.
+ ConstantInt *CI = dyn_cast<ConstantInt>(Cmp.getOperand(1));
+ if (!CI)
+ return nullptr;
+
// Canonicalize icmp instructions based on dominating conditions.
BasicBlock *Parent = Cmp.getParent();
BasicBlock *Dom = Parent->getSinglePredecessor();
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h?rev=281663&r1=281662&r2=281663&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h Thu Sep 15 16:35:30 2016
@@ -549,9 +549,9 @@ private:
Instruction *foldFCmpIntToFPConst(FCmpInst &I, Instruction *LHSI,
Constant *RHSC);
Instruction *foldICmpCstShrConst(ICmpInst &I, Value *Op, Value *A,
- ConstantInt *CI1, ConstantInt *CI2);
+ const APInt &C1, const APInt &C2);
Instruction *foldICmpCstShlConst(ICmpInst &I, Value *Op, Value *A,
- ConstantInt *CI1, ConstantInt *CI2);
+ const APInt &C1, const APInt &C2);
Instruction *foldICmpAddOpConst(Instruction &ICI, Value *X, ConstantInt *CI,
ICmpInst::Predicate Pred);
Instruction *foldICmpWithCastAndCast(ICmpInst &ICI);
Modified: llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll?rev=281663&r1=281662&r2=281663&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/icmp-shr.ll Thu Sep 15 16:35:30 2016
@@ -13,6 +13,16 @@ define i1 @lshr_eq_msb_low_last_zero(i8
ret i1 %cmp
}
+define <2 x i1> @lshr_eq_msb_low_last_zero_vec(<2 x i8> %a) {
+; CHECK-LABEL: @lshr_eq_msb_low_last_zero_vec(
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i8> %a, <i8 6, i8 6>
+; CHECK-NEXT: ret <2 x i1> [[CMP]]
+;
+ %shr = lshr <2 x i8> <i8 127, i8 127>, %a
+ %cmp = icmp eq <2 x i8> %shr, zeroinitializer
+ ret <2 x i1> %cmp
+}
+
define i1 @ashr_eq_msb_low_second_zero(i8 %a) {
; CHECK-LABEL: @ashr_eq_msb_low_second_zero(
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i8 %a, 6
Modified: llvm/trunk/test/Transforms/InstCombine/icmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp.ll?rev=281663&r1=281662&r2=281663&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/icmp.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/icmp.ll Thu Sep 15 16:35:30 2016
@@ -2194,6 +2194,16 @@ define i1 @shl_ap1_zero_ap2_non_zero_2(i
ret i1 %cmp
}
+define <2 x i1> @shl_ap1_zero_ap2_non_zero_2_vec(<2 x i32> %a) {
+; CHECK-LABEL: @shl_ap1_zero_ap2_non_zero_2_vec(
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i32> %a, <i32 29, i32 29>
+; CHECK-NEXT: ret <2 x i1> [[CMP]]
+;
+ %shl = shl <2 x i32> <i32 4, i32 4>, %a
+ %cmp = icmp eq <2 x i32> %shl, zeroinitializer
+ ret <2 x i1> %cmp
+}
+
define i1 @shl_ap1_zero_ap2_non_zero_4(i32 %a) {
; CHECK-LABEL: @shl_ap1_zero_ap2_non_zero_4(
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 %a, 30
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