[PATCH] D138180: InstCombine: Fold negations of is_fpclass intrinsics

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
arsenm added reviewers: sepavloff, spatel, kpn, andrew.w.kaylor, jcranmer-intel, foad.
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arsenm requested review of this revision.
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Can invert the result by inverting the test mask.


https://reviews.llvm.org/D138180

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  llvm/test/Transforms/InstCombine/is_fpclass.ll


Index: llvm/test/Transforms/InstCombine/is_fpclass.ll
===================================================================
--- llvm/test/Transforms/InstCombine/is_fpclass.ll
+++ llvm/test/Transforms/InstCombine/is_fpclass.ll
@@ -417,9 +417,8 @@
 
 define i1 @test_class_not_is_inf_nan(float %x) {
 ; CHECK-LABEL: @test_class_not_is_inf_nan(
-; CHECK-NEXT:    [[CLASS:%.*]] = call i1 @llvm.is.fpclass.f32(float [[X:%.*]], i32 519)
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[CLASS]], true
-; CHECK-NEXT:    ret i1 [[NOT]]
+; CHECK-NEXT:    [[CLASS:%.*]] = call i1 @llvm.is.fpclass.f32(float [[X:%.*]], i32 504)
+; CHECK-NEXT:    ret i1 [[CLASS]]
 ;
   %class = call i1 @llvm.is.fpclass.f32(float %x, i32 519)
   %not = xor i1 %class, true
@@ -428,9 +427,8 @@
 
 define i1 @test_class_not_is_normal(float %x) {
 ; CHECK-LABEL: @test_class_not_is_normal(
-; CHECK-NEXT:    [[CLASS:%.*]] = call i1 @llvm.is.fpclass.f32(float [[X:%.*]], i32 264)
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[CLASS]], true
-; CHECK-NEXT:    ret i1 [[NOT]]
+; CHECK-NEXT:    [[CLASS:%.*]] = call i1 @llvm.is.fpclass.f32(float [[X:%.*]], i32 759)
+; CHECK-NEXT:    ret i1 [[CLASS]]
 ;
   %class = call i1 @llvm.is.fpclass.f32(float %x, i32 264)
   %not = xor i1 %class, true
@@ -449,9 +447,8 @@
 
 define <2 x i1> @test_class_not_vector(<2 x float> %x) {
 ; CHECK-LABEL: @test_class_not_vector(
-; CHECK-NEXT:    [[CLASS:%.*]] = call <2 x i1> @llvm.is.fpclass.v2f32(<2 x float> [[X:%.*]], i32 33)
-; CHECK-NEXT:    [[NOT:%.*]] = xor <2 x i1> [[CLASS]], <i1 true, i1 true>
-; CHECK-NEXT:    ret <2 x i1> [[NOT]]
+; CHECK-NEXT:    [[CLASS:%.*]] = call <2 x i1> @llvm.is.fpclass.v2f32(<2 x float> [[X:%.*]], i32 990)
+; CHECK-NEXT:    ret <2 x i1> [[CLASS]]
 ;
   %class = call <2 x i1> @llvm.is.fpclass.v2f32(<2 x float> %x, i32 33)
   %not = xor <2 x i1> %class, <i1 true, i1 true>
Index: llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -3709,6 +3709,14 @@
       Value *InvMaxMin = Builder.CreateBinaryIntrinsic(InvID, X, NotY);
       return replaceInstUsesWith(I, InvMaxMin);
     }
+
+    if (II->getIntrinsicID() == Intrinsic::is_fpclass) {
+      ConstantInt *ClassMask = cast<ConstantInt>(II->getArgOperand(1));
+      II->setArgOperand(
+          1, ConstantInt::get(ClassMask->getType(),
+                              ~ClassMask->getZExtValue() & fcAllFlags));
+      return replaceInstUsesWith(I, II);
+    }
   }
 
   if (NotOp->hasOneUse()) {


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