[PATCH] D36234: [InstCombine] Support sext in foldLogicCastConstant

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.

This adds support for sext in foldLogicCastConstant. This is a prerequisite for https://reviews.llvm.org/D36214.

Not clear if the test changes are a win or not.

Could reduce the handling to only do all 0s/1s constants which would be sufficient for what's needed in https://reviews.llvm.org/D36214.


https://reviews.llvm.org/D36234

Files:
  lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  test/Transforms/InstCombine/cast.ll
  test/Transforms/InstCombine/logical-select.ll
  test/Transforms/SLPVectorizer/X86/minimum-sizes.ll


Index: test/Transforms/SLPVectorizer/X86/minimum-sizes.ll
===================================================================
--- test/Transforms/SLPVectorizer/X86/minimum-sizes.ll
+++ test/Transforms/SLPVectorizer/X86/minimum-sizes.ll
@@ -48,12 +48,12 @@
 ;        optimization, we make the proposed smaller type (i8) larger (i16) to
 ;        ensure correctness.
 ;
-; CHECK: %[[S0:.+]] = sext <2 x i8> {{.*}} to <2 x i16>
-; CHECK: %[[OR:.+]] = or <2 x i16> %[[S0]], <i16 1, i16 1>
-; CHECK: %[[E0:.+]] = extractelement <2 x i16> %[[OR]], i32 0
+; CHECK: %[[OR:.+]] = or <2 x i8> {{.*}}, <i8 1, i8 1>
+; CHECK: %[[S0:.+]] = sext <2 x i8> %[[OR]] to <2 x i16>
+; CHECK: %[[E0:.+]] = extractelement <2 x i16> %[[S0]], i32 0
 ; CHECK: %[[S1:.+]] = sext i16 %[[E0]] to i64
 ; CHECK: getelementptr inbounds i8, i8* %ptr, i64 %[[S1]]
-; CHECK: %[[E1:.+]] = extractelement <2 x i16> %[[OR]], i32 1
+; CHECK: %[[E1:.+]] = extractelement <2 x i16> %[[S0]], i32 1
 ; CHECK: %[[S2:.+]] = sext i16 %[[E1]] to i64
 ; CHECK: getelementptr inbounds i8, i8* %ptr, i64 %[[S2]]
 ;
Index: test/Transforms/InstCombine/logical-select.ll
===================================================================
--- test/Transforms/InstCombine/logical-select.ll
+++ test/Transforms/InstCombine/logical-select.ll
@@ -504,11 +504,11 @@
 
 define <4 x i32> @vec_sel_xor_multi_use(<4 x i32> %a, <4 x i32> %b, <4 x i1> %c) {
 ; CHECK-LABEL: @vec_sel_xor_multi_use(
-; CHECK-NEXT:    [[MASK:%.*]] = sext <4 x i1> %c to <4 x i32>
-; CHECK-NEXT:    [[MASK_FLIP1:%.*]] = xor <4 x i32> [[MASK]], <i32 -1, i32 0, i32 0, i32 0>
-; CHECK-NEXT:    [[TMP1:%.*]] = xor <4 x i1> %c, <i1 false, i1 true, i1 true, i1 true>
-; CHECK-NEXT:    [[TMP2:%.*]] = select <4 x i1> [[TMP1]], <4 x i32> %a, <4 x i32> %b
-; CHECK-NEXT:    [[ADD:%.*]] = add <4 x i32> [[TMP2]], [[MASK_FLIP1]]
+; CHECK-NEXT:    [[TMP1:%.*]] = xor <4 x i1> [[C:%.*]], <i1 true, i1 false, i1 false, i1 false>
+; CHECK-NEXT:    [[MASK_FLIP1:%.*]] = sext <4 x i1> [[TMP1]] to <4 x i32>
+; CHECK-NEXT:    [[TMP2:%.*]] = xor <4 x i1> [[C]], <i1 false, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[TMP3:%.*]] = select <4 x i1> [[TMP2]], <4 x i32> [[A:%.*]], <4 x i32> [[B:%.*]]
+; CHECK-NEXT:    [[ADD:%.*]] = add <4 x i32> [[TMP3]], [[MASK_FLIP1]]
 ; CHECK-NEXT:    ret <4 x i32> [[ADD]]
 ;
   %mask = sext <4 x i1> %c to <4 x i32>
Index: test/Transforms/InstCombine/cast.ll
===================================================================
--- test/Transforms/InstCombine/cast.ll
+++ test/Transforms/InstCombine/cast.ll
@@ -587,9 +587,9 @@
 
 define i64 @test47(i8 %A) {
 ; CHECK-LABEL: @test47(
-; CHECK-NEXT:    [[B:%.*]] = sext i8 %A to i64
-; CHECK-NEXT:    [[C:%.*]] = and i64 [[B]], 4294967253
-; CHECK-NEXT:    [[E:%.*]] = or i64 [[C]], 42
+; CHECK-NEXT:    [[TMP1:%.*]] = or i8 [[A:%.*]], 42
+; CHECK-NEXT:    [[C:%.*]] = sext i8 [[TMP1]] to i64
+; CHECK-NEXT:    [[E:%.*]] = and i64 [[C]], 4294967295
 ; CHECK-NEXT:    ret i64 [[E]]
 ;
   %B = sext i8 %A to i32
Index: lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1104,6 +1104,16 @@
     }
   }
 
+  if (match(Cast, m_OneUse(m_SExt(m_Value(X))))) {
+    Constant *TruncC = ConstantExpr::getTrunc(C, SrcTy);
+    Constant *SextTruncC = ConstantExpr::getSExt(TruncC, DestTy);
+    if (SextTruncC == C) {
+      // LogicOpc (sext X), C --> sext (LogicOpc X, C)
+      Value *NewOp = Builder.CreateBinOp(LogicOpc, X, TruncC);
+      return new SExtInst(NewOp, DestTy);
+    }
+  }
+
   return nullptr;
 }
 


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