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

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
arsenm added a reviewer: spatel.
Herald added a subscriber: wdng.

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
@@ -84,3 +84,46 @@
   ret float %r
 }
 
+define i1 @extractelt_vector_icmp_constrhs(<2 x i32> %arg) {
+; CHECK-LABEL: @extractelt_vector_icmp_constrhs(
+; 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
+  %ext = extractelement <2 x i1> %cmp, i32 0
+  ret i1 %ext
+}
+
+define i1 @extractelt_vector_fcmp_constrhs(<2 x float> %arg) {
+; CHECK-LABEL: @extractelt_vector_fcmp_constrhs(
+; 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
+  %ext = extractelement <2 x i1> %cmp, i32 0
+  ret i1 %ext
+}
+
+define i1 @extractelt_vector_icmp_constrhs_dynidx(<2 x i32> %arg, i32 %idx) {
+; CHECK-LABEL: @extractelt_vector_icmp_constrhs_dynidx(
+; 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
+  %ext = extractelement <2 x i1> %cmp, i32 %idx
+  ret i1 %ext
+}
+
+define i1 @extractelt_vector_fcmp_constrhs_dynidx(<2 x float> %arg, i32 %idx) {
+; CHECK-LABEL: @extractelt_vector_fcmp_constrhs_dynidx(
+; 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
+  %ext = extractelement <2 x i1> %cmp, i32 %idx
+  ret i1 %ext
+}
Index: lib/Transforms/InstCombine/InstCombineVectorOps.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ lib/Transforms/InstCombine/InstCombineVectorOps.cpp
@@ -365,6 +365,21 @@
         Worklist.AddValue(EE);
         return CastInst::Create(CI->getOpcode(), EE, EI.getType());
       }
+    } 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());
+      }
     }
   }
   return nullptr;


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