From 5ccbd07dd607bac8a05016d80e3fa34f2d393279 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault@amd.com>
Date: Wed, 16 Nov 2022 20:51:40 -0800
Subject: [PATCH] InstCombine: Fold out is_fpclass inf checks from test mask
 for known finite sources

Make the partner transform already done for nnan sources.
---
 .../Transforms/InstCombine/InstCombineCalls.cpp    | 12 ++++++++++++
 llvm/test/Transforms/InstCombine/is_fpclass.ll     | 22 ++++++----------------
 2 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index bb98693..2fe8dbe 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -866,6 +866,18 @@ Instruction *InstCombinerImpl::foldIntrinsicIsFPClass(IntrinsicInst &II) {
     return replaceInstUsesWith(II, ConstantInt::get(II.getType(), true));
   }
 
+  // fp_class (ninf x), ninf|pinf|other -> fp_class (ninf x), other
+  if ((Mask & fcInf) && isKnownNeverInfinity(Src0, &getTargetLibraryInfo())) {
+    II.setArgOperand(1, ConstantInt::get(Src1->getType(), Mask & ~fcInf));
+    return &II;
+  }
+
+  // fp_class (ninf x), ~(ninf|pinf) -> true
+  if (Mask == (~fcInf & fcAllFlags) &&
+      isKnownNeverInfinity(Src0, &getTargetLibraryInfo())) {
+    return replaceInstUsesWith(II, ConstantInt::get(II.getType(), true));
+  }
+
   return nullptr;
 }
 
diff --git a/llvm/test/Transforms/InstCombine/is_fpclass.ll b/llvm/test/Transforms/InstCombine/is_fpclass.ll
index fae4162..605f075 100644
--- a/llvm/test/Transforms/InstCombine/is_fpclass.ll
+++ b/llvm/test/Transforms/InstCombine/is_fpclass.ll
@@ -469,9 +469,7 @@ define i1 @test_class_is_not_nan_nnan_src_strict(float %x) {
 
 define i1 @test_class_is_ninf_pinf_ninf_src(float %x) {
 ; CHECK-LABEL: @test_class_is_ninf_pinf_ninf_src(
-; CHECK-NEXT:    [[NINF:%.*]] = fadd ninf float [[X:%.*]], 1.000000e+00
-; CHECK-NEXT:    [[CLASS:%.*]] = call i1 @llvm.is.fpclass.f32(float [[NINF]], i32 516)
-; CHECK-NEXT:    ret i1 [[CLASS]]
+; CHECK-NEXT:    ret i1 false
 ;
   %ninf = fadd ninf float %x, 1.0
   %class = call i1 @llvm.is.fpclass.f32(float %ninf, i32 516)
@@ -480,9 +478,7 @@ define i1 @test_class_is_ninf_pinf_ninf_src(float %x) {
 
 define i1 @test_class_is_ninf_ninf_src(float %x) {
 ; CHECK-LABEL: @test_class_is_ninf_ninf_src(
-; CHECK-NEXT:    [[NINF:%.*]] = fadd ninf float [[X:%.*]], 1.000000e+00
-; CHECK-NEXT:    [[CLASS:%.*]] = call i1 @llvm.is.fpclass.f32(float [[NINF]], i32 4)
-; CHECK-NEXT:    ret i1 [[CLASS]]
+; CHECK-NEXT:    ret i1 false
 ;
   %ninf = fadd ninf float %x, 1.0
   %class = call i1 @llvm.is.fpclass.f32(float %ninf, i32 4)
@@ -491,9 +487,7 @@ define i1 @test_class_is_ninf_ninf_src(float %x) {
 
 define i1 @test_class_is_pinf_ninf_src(float %x) {
 ; CHECK-LABEL: @test_class_is_pinf_ninf_src(
-; CHECK-NEXT:    [[NINF:%.*]] = fadd ninf float [[X:%.*]], 1.000000e+00
-; CHECK-NEXT:    [[CLASS:%.*]] = call i1 @llvm.is.fpclass.f32(float [[NINF]], i32 512)
-; CHECK-NEXT:    ret i1 [[CLASS]]
+; CHECK-NEXT:    ret i1 false
 ;
   %ninf = fadd ninf float %x, 1.0
   %class = call i1 @llvm.is.fpclass.f32(float %ninf, i32 512)
@@ -503,7 +497,7 @@ define i1 @test_class_is_pinf_ninf_src(float %x) {
 define i1 @test_class_is_ninf_pinf_pnormal_ninf_src(float %x) {
 ; CHECK-LABEL: @test_class_is_ninf_pinf_pnormal_ninf_src(
 ; CHECK-NEXT:    [[NINF:%.*]] = fadd ninf float [[X:%.*]], 1.000000e+00
-; CHECK-NEXT:    [[CLASS:%.*]] = call i1 @llvm.is.fpclass.f32(float [[NINF]], i32 772)
+; CHECK-NEXT:    [[CLASS:%.*]] = call i1 @llvm.is.fpclass.f32(float [[NINF]], i32 256)
 ; CHECK-NEXT:    ret i1 [[CLASS]]
 ;
   %ninf = fadd ninf float %x, 1.0
@@ -513,9 +507,7 @@ define i1 @test_class_is_ninf_pinf_pnormal_ninf_src(float %x) {
 
 define i1 @test_class_is_not_inf_ninf_src(float %x) {
 ; CHECK-LABEL: @test_class_is_not_inf_ninf_src(
-; CHECK-NEXT:    [[NINF:%.*]] = fadd ninf float [[X:%.*]], 1.000000e+00
-; CHECK-NEXT:    [[CLASS:%.*]] = call i1 @llvm.is.fpclass.f32(float [[NINF]], i32 507)
-; CHECK-NEXT:    ret i1 [[CLASS]]
+; CHECK-NEXT:    ret i1 true
 ;
   %ninf = fadd ninf float %x, 1.0
   %class = call i1 @llvm.is.fpclass.f32(float %ninf, i32 507) ; ~fcInf & fcAllFlags
@@ -524,9 +516,7 @@ define i1 @test_class_is_not_inf_ninf_src(float %x) {
 
 define i1 @test_class_is_not_inf_ninf_src_strict(float %x) {
 ; CHECK-LABEL: @test_class_is_not_inf_ninf_src_strict(
-; CHECK-NEXT:    [[NINF:%.*]] = fadd ninf float [[X:%.*]], 1.000000e+00
-; CHECK-NEXT:    [[CLASS:%.*]] = call i1 @llvm.is.fpclass.f32(float [[NINF]], i32 507) #[[ATTR2]]
-; CHECK-NEXT:    ret i1 [[CLASS]]
+; CHECK-NEXT:    ret i1 true
 ;
   %ninf = fadd ninf float %x, 1.0
   %class = call i1 @llvm.is.fpclass.f32(float %ninf, i32 507) strictfp ; ~fcInf & fcAllFlags
-- 
2.7.4