[llvm] r298520 - [InstCombine] canonicalize insertelement of scalar constant ahead of insertelement of variable
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Wed Mar 22 10:10:44 PDT 2017
Author: spatel
Date: Wed Mar 22 12:10:44 2017
New Revision: 298520
URL: http://llvm.org/viewvc/llvm-project?rev=298520&view=rev
Log:
[InstCombine] canonicalize insertelement of scalar constant ahead of insertelement of variable
insertelement (insertelement X, Y, IdxC1), ScalarC, IdxC2 -->
insertelement (insertelement X, ScalarC, IdxC2), Y, IdxC1
As noted in the code comment and seen in the test changes, the motivation is that by pulling
constant insertion up, we may be able to constant fold some insertelement instructions.
Differential Revision: https://reviews.llvm.org/D31196
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
llvm/trunk/test/Transforms/InstCombine/bitcast-bigendian.ll
llvm/trunk/test/Transforms/InstCombine/insert-extract-shuffle.ll
llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll
llvm/trunk/test/Transforms/InstCombine/vector_insertelt_shuffle.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp?rev=298520&r1=298519&r2=298520&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp Wed Mar 22 12:10:44 2017
@@ -645,6 +645,36 @@ static Instruction *foldInsSequenceIntoB
return new ShuffleVectorInst(InsertFirst, UndefValue::get(VT), ZeroMask);
}
+/// If we have an insertelement instruction feeding into another insertelement
+/// and the 2nd is inserting a constant into the vector, canonicalize that
+/// constant insertion before the insertion of a variable:
+///
+/// insertelement (insertelement X, Y, IdxC1), ScalarC, IdxC2 -->
+/// insertelement (insertelement X, ScalarC, IdxC2), Y, IdxC1
+///
+/// This has the potential of eliminating the 2nd insertelement instruction
+/// via constant folding of the scalar constant into a vector constant.
+static Instruction *hoistInsEltConst(InsertElementInst &InsElt2,
+ InstCombiner::BuilderTy &Builder) {
+ auto *InsElt1 = dyn_cast<InsertElementInst>(InsElt2.getOperand(0));
+ if (!InsElt1 || !InsElt1->hasOneUse())
+ return nullptr;
+
+ Value *X, *Y;
+ Constant *ScalarC;
+ ConstantInt *IdxC1, *IdxC2;
+ if (match(InsElt1->getOperand(0), m_Value(X)) &&
+ match(InsElt1->getOperand(1), m_Value(Y)) && !isa<Constant>(Y) &&
+ match(InsElt1->getOperand(2), m_ConstantInt(IdxC1)) &&
+ match(InsElt2.getOperand(1), m_Constant(ScalarC)) &&
+ match(InsElt2.getOperand(2), m_ConstantInt(IdxC2)) && IdxC1 != IdxC2) {
+ Value *NewInsElt1 = Builder.CreateInsertElement(X, ScalarC, IdxC2);
+ return InsertElementInst::Create(NewInsElt1, Y, IdxC1);
+ }
+
+ return nullptr;
+}
+
/// insertelt (shufflevector X, CVec, Mask|insertelt X, C1, CIndex1), C, CIndex
/// --> shufflevector X, CVec', Mask'
static Instruction *foldConstantInsEltIntoShuffle(InsertElementInst &InsElt) {
@@ -806,6 +836,9 @@ Instruction *InstCombiner::visitInsertEl
if (Instruction *Shuf = foldConstantInsEltIntoShuffle(IE))
return Shuf;
+ if (Instruction *NewInsElt = hoistInsEltConst(IE, *Builder))
+ return NewInsElt;
+
// Turn a sequence of inserts that broadcasts a scalar into a single
// insert + shufflevector.
if (Instruction *Broadcast = foldInsSequenceIntoBroadcast(IE))
Modified: llvm/trunk/test/Transforms/InstCombine/bitcast-bigendian.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/bitcast-bigendian.ll?rev=298520&r1=298519&r2=298520&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/bitcast-bigendian.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/bitcast-bigendian.ll Wed Mar 22 12:10:44 2017
@@ -81,9 +81,8 @@ define <2 x float> @test5(float %A, floa
define <2 x float> @test6(float %A){
; CHECK-LABEL: @test6(
-; CHECK-NEXT: [[TMP1:%.*]] = insertelement <2 x float> undef, float %A, i32 0
-; CHECK-NEXT: [[TMP2:%.*]] = insertelement <2 x float> [[TMP1]], float 4.200000e+01, i32 1
-; CHECK-NEXT: ret <2 x float> [[TMP2]]
+; CHECK-NEXT: [[TMP1:%.*]] = insertelement <2 x float> <float undef, float 4.200000e+01>, float %A, i32 0
+; CHECK-NEXT: ret <2 x float> [[TMP1]]
;
%tmp23 = bitcast float %A to i32
%tmp24 = zext i32 %tmp23 to i64
Modified: llvm/trunk/test/Transforms/InstCombine/insert-extract-shuffle.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/insert-extract-shuffle.ll?rev=298520&r1=298519&r2=298520&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/insert-extract-shuffle.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/insert-extract-shuffle.ll Wed Mar 22 12:10:44 2017
@@ -86,11 +86,8 @@ define <8 x float> @widen_extract4(<8 x
define <8 x i16> @pr26015(<4 x i16> %t0) {
; CHECK-LABEL: @pr26015(
-; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <4 x i16> %t0, <4 x i16> undef, <8 x i32> <i32 undef, i32 undef, i32 undef, i32 3, i32 undef, i32 undef, i32 undef, i32 undef>
-; CHECK-NEXT: [[TMP2:%.*]] = extractelement <4 x i16> %t0, i32 2
-; CHECK-NEXT: [[T2:%.*]] = insertelement <8 x i16> <i16 0, i16 0, i16 0, i16 undef, i16 0, i16 0, i16 undef, i16 undef>, i16 [[TMP2]], i32 3
-; CHECK-NEXT: [[T3:%.*]] = insertelement <8 x i16> [[T2]], i16 0, i32 6
-; CHECK-NEXT: [[T5:%.*]] = shufflevector <8 x i16> [[T3]], <8 x i16> [[TMP1]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 11>
+; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <4 x i16> %t0, <4 x i16> undef, <8 x i32> <i32 undef, i32 undef, i32 2, i32 3, i32 undef, i32 undef, i32 undef, i32 undef>
+; CHECK-NEXT: [[T5:%.*]] = shufflevector <8 x i16> <i16 0, i16 0, i16 0, i16 undef, i16 0, i16 0, i16 0, i16 undef>, <8 x i16> [[TMP1]], <8 x i32> <i32 0, i32 1, i32 2, i32 10, i32 4, i32 5, i32 6, i32 11>
; CHECK-NEXT: ret <8 x i16> [[T5]]
;
%t1 = extractelement <4 x i16> %t0, i32 2
@@ -110,8 +107,7 @@ define <8 x i16> @pr25999(<4 x i16> %t0,
; CHECK-NEXT: br i1 %b, label %if, label %end
; CHECK: if:
; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <4 x i16> %t0, <4 x i16> undef, <8 x i32> <i32 undef, i32 undef, i32 undef, i32 3, i32 undef, i32 undef, i32 undef, i32 undef>
-; CHECK-NEXT: [[T2:%.*]] = insertelement <8 x i16> <i16 0, i16 0, i16 0, i16 undef, i16 0, i16 0, i16 undef, i16 undef>, i16 [[T1]], i32 3
-; CHECK-NEXT: [[T3:%.*]] = insertelement <8 x i16> [[T2]], i16 0, i32 6
+; CHECK-NEXT: [[T3:%.*]] = insertelement <8 x i16> <i16 0, i16 0, i16 0, i16 undef, i16 0, i16 0, i16 0, i16 undef>, i16 [[T1]], i32 3
; CHECK-NEXT: [[T5:%.*]] = shufflevector <8 x i16> [[T3]], <8 x i16> [[TMP1]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 11>
; CHECK-NEXT: ret <8 x i16> [[T5]]
; CHECK: end:
Modified: llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll?rev=298520&r1=298519&r2=298520&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll Wed Mar 22 12:10:44 2017
@@ -182,10 +182,9 @@ define <4 x float> @dead_shuffle_elt(<4
define <2 x float> @test_fptrunc(double %f) {
; CHECK-LABEL: @test_fptrunc(
-; CHECK-NEXT: [[TMP1:%.*]] = insertelement <2 x double> undef, double %f, i32 0
-; CHECK-NEXT: [[TMP2:%.*]] = insertelement <2 x double> [[TMP1]], double 0.000000e+00, i32 1
-; CHECK-NEXT: [[TMP3:%.*]] = fptrunc <2 x double> [[TMP2]] to <2 x float>
-; CHECK-NEXT: ret <2 x float> [[TMP3]]
+; CHECK-NEXT: [[TMP1:%.*]] = insertelement <2 x double> <double undef, double 0.000000e+00>, double %f, i32 0
+; CHECK-NEXT: [[TMP2:%.*]] = fptrunc <2 x double> [[TMP1]] to <2 x float>
+; CHECK-NEXT: ret <2 x float> [[TMP2]]
;
%tmp9 = insertelement <4 x double> undef, double %f, i32 0
%tmp10 = insertelement <4 x double> %tmp9, double 0.000000e+00, i32 1
@@ -198,10 +197,9 @@ define <2 x float> @test_fptrunc(double
define <2 x double> @test_fpext(float %f) {
; CHECK-LABEL: @test_fpext(
-; CHECK-NEXT: [[TMP1:%.*]] = insertelement <2 x float> undef, float %f, i32 0
-; CHECK-NEXT: [[TMP2:%.*]] = insertelement <2 x float> [[TMP1]], float 0.000000e+00, i32 1
-; CHECK-NEXT: [[TMP3:%.*]] = fpext <2 x float> [[TMP2]] to <2 x double>
-; CHECK-NEXT: ret <2 x double> [[TMP3]]
+; CHECK-NEXT: [[TMP1:%.*]] = insertelement <2 x float> <float undef, float 0.000000e+00>, float %f, i32 0
+; CHECK-NEXT: [[TMP2:%.*]] = fpext <2 x float> [[TMP1]] to <2 x double>
+; CHECK-NEXT: ret <2 x double> [[TMP2]]
;
%tmp9 = insertelement <4 x float> undef, float %f, i32 0
%tmp10 = insertelement <4 x float> %tmp9, float 0.000000e+00, i32 1
@@ -223,8 +221,7 @@ define <4 x double> @test_shuffle(<4 x d
define <4 x float> @test_select(float %f, float %g) {
; CHECK-LABEL: @test_select(
-; CHECK-NEXT: [[A0:%.*]] = insertelement <4 x float> undef, float %f, i32 0
-; CHECK-NEXT: [[A3:%.*]] = insertelement <4 x float> [[A0]], float 3.000000e+00, i32 3
+; CHECK-NEXT: [[A3:%.*]] = insertelement <4 x float> <float undef, float undef, float undef, float 3.000000e+00>, float %f, i32 0
; CHECK-NEXT: [[RET:%.*]] = shufflevector <4 x float> [[A3]], <4 x float> <float undef, float 4.000000e+00, float 5.000000e+00, float undef>, <4 x i32> <i32 0, i32 5, i32 6, i32 3>
; CHECK-NEXT: ret <4 x float> [[RET]]
;
Modified: llvm/trunk/test/Transforms/InstCombine/vector_insertelt_shuffle.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/vector_insertelt_shuffle.ll?rev=298520&r1=298519&r2=298520&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/vector_insertelt_shuffle.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/vector_insertelt_shuffle.ll Wed Mar 22 12:10:44 2017
@@ -12,10 +12,12 @@ define <4 x float> @foo(<4 x float> %x)
ret <4 x float> %ins2
}
+; Insert of a constant is canonicalized ahead of insert of a variable.
+
define <4 x float> @bar(<4 x float> %x, float %a) {
; CHECK-LABEL: @bar(
-; CHECK-NEXT: [[INS1:%.*]] = insertelement <4 x float> %x, float %a, i32 1
-; CHECK-NEXT: [[INS2:%.*]] = insertelement <4 x float> [[INS1]], float 2.000000e+00, i32 2
+; CHECK-NEXT: [[TMP1:%.*]] = insertelement <4 x float> %x, float 2.000000e+00, i32 2
+; CHECK-NEXT: [[INS2:%.*]] = insertelement <4 x float> [[TMP1]], float %a, i32 1
; CHECK-NEXT: ret <4 x float> [[INS2]]
;
%ins1 = insertelement<4 x float> %x, float %a, i32 1
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