[PATCH] D55182: InstCombine: Scalarize single use icmp/fcmp

[Matt Arsenault via Phabricator via llvm-commits]

arsenm updated this revision to Diff 176679.
arsenm added a comment.

Rearrange code, apply on top of existing tests


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D55182/new/

https://reviews.llvm.org/D55182

Files:
  lib/Transforms/InstCombine/InstCombineVectorOps.cpp
  test/Transforms/InstCombine/scalarization.ll


Index: test/Transforms/InstCombine/scalarization.ll
===================================================================
--- test/Transforms/InstCombine/scalarization.ll
+++ test/Transforms/InstCombine/scalarization.ll
@@ -86,8 +86,8 @@
 
 define i1 @extractelt_vector_icmp_constrhs(<2 x i32> %arg) {
 ; CHECK-LABEL: @extractelt_vector_icmp_constrhs(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <2 x i32> [[ARG:%.*]], zeroinitializer
-; CHECK-NEXT:    [[EXT:%.*]] = extractelement <2 x i1> [[CMP]], i32 0
+; CHECK-NEXT:    [[EXT_LHS:%.*]] = extractelement <2 x i32> [[ARG:%.*]], i32 0
+; CHECK-NEXT:    [[EXT:%.*]] = icmp eq i32 [[EXT_LHS]], 0
 ; CHECK-NEXT:    ret i1 [[EXT]]
 ;
   %cmp = icmp eq <2 x i32> %arg, zeroinitializer
@@ -97,8 +97,8 @@
 
 define i1 @extractelt_vector_fcmp_constrhs(<2 x float> %arg) {
 ; CHECK-LABEL: @extractelt_vector_fcmp_constrhs(
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp oeq <2 x float> [[ARG:%.*]], zeroinitializer
-; CHECK-NEXT:    [[EXT:%.*]] = extractelement <2 x i1> [[CMP]], i32 0
+; CHECK-NEXT:    [[EXT_LHS:%.*]] = extractelement <2 x float> [[ARG:%.*]], i32 0
+; CHECK-NEXT:    [[EXT:%.*]] = fcmp oeq float [[EXT_LHS]], 0.000000e+00
 ; CHECK-NEXT:    ret i1 [[EXT]]
 ;
   %cmp = fcmp oeq <2 x float> %arg, zeroinitializer
@@ -108,8 +108,8 @@
 
 define i1 @extractelt_vector_icmp_constrhs_dynidx(<2 x i32> %arg, i32 %idx) {
 ; CHECK-LABEL: @extractelt_vector_icmp_constrhs_dynidx(
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq <2 x i32> [[ARG:%.*]], zeroinitializer
-; CHECK-NEXT:    [[EXT:%.*]] = extractelement <2 x i1> [[CMP]], i32 [[IDX:%.*]]
+; CHECK-NEXT:    [[EXT_LHS:%.*]] = extractelement <2 x i32> [[ARG:%.*]], i32 [[IDX:%.*]]
+; CHECK-NEXT:    [[EXT:%.*]] = icmp eq i32 [[EXT_LHS]], 0
 ; CHECK-NEXT:    ret i1 [[EXT]]
 ;
   %cmp = icmp eq <2 x i32> %arg, zeroinitializer
@@ -119,8 +119,8 @@
 
 define i1 @extractelt_vector_fcmp_constrhs_dynidx(<2 x float> %arg, i32 %idx) {
 ; CHECK-LABEL: @extractelt_vector_fcmp_constrhs_dynidx(
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp oeq <2 x float> [[ARG:%.*]], zeroinitializer
-; CHECK-NEXT:    [[EXT:%.*]] = extractelement <2 x i1> [[CMP]], i32 [[IDX:%.*]]
+; CHECK-NEXT:    [[EXT_LHS:%.*]] = extractelement <2 x float> [[ARG:%.*]], i32 [[IDX:%.*]]
+; CHECK-NEXT:    [[EXT:%.*]] = fcmp oeq float [[EXT_LHS]], 0.000000e+00
 ; CHECK-NEXT:    ret i1 [[EXT]]
 ;
   %cmp = fcmp oeq <2 x float> %arg, zeroinitializer
Index: lib/Transforms/InstCombine/InstCombineVectorOps.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ lib/Transforms/InstCombine/InstCombineVectorOps.cpp
@@ -322,6 +322,18 @@
         return BinaryOperator::CreateWithCopiedFlags(BO->getOpcode(),
                                                      newEI0, newEI1, BO);
       }
+    } else if (CmpInst *CI = dyn_cast<CmpInst>(I)) {
+      if (CI->hasOneUse() &&
+          cheapToScalarize(CI, isa<ConstantInt>(EI.getOperand(1)))) {
+        Value *newEI0 =
+          Builder.CreateExtractElement(CI->getOperand(0), EI.getOperand(1),
+                                       EI.getName()+".lhs");
+        Value *newEI1 =
+          Builder.CreateExtractElement(CI->getOperand(1), EI.getOperand(1),
+                                       EI.getName()+".rhs");
+        return CmpInst::Create(CI->getOpcode(), CI->getPredicate(),
+                               newEI0, newEI1, CI->getName());
+      }
     } else if (InsertElementInst *IE = dyn_cast<InsertElementInst>(I)) {
       // Extracting the inserted element?
       if (IE->getOperand(2) == EI.getOperand(1))


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