Attributor: Allow refining of callsite attributes that already have nofpclass

[arsenm]

d2a06ef05a22211b8b2cefdd1e68d2a54ddc86ce

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

if (isa<UndefValue>(V)) {
       indicateOptimisticFixpoint();
       return;
     }
 
     SmallVector<Attribute> Attrs;
     A.getAttrs(getIRPosition(), {Attribute::NoFPClass}, Attrs, false);
     for (const auto &Attr : Attrs) {
       addKnownBits(Attr.getNoFPClass());
-      return;
     }
 
     const DataLayout &DL = A.getDataLayout();
     if (getPositionKind() != IRPosition::IRP_RETURNED) {
       KnownFPClass KnownFPClass = computeKnownFPClass(&V, DL);
       addKnownBits(~KnownFPClass.KnownFPClasses);
     }
 

llvm/test/Transforms/Attributor/nofpclass.ll

 ;
   %add = fadd float %arg0, %arg1
   ret float %add
 }
 
 define internal float @returns_fence(float %arg) {
 ; TUNIT: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
 ; TUNIT-LABEL: define internal float @returns_fence
-; TUNIT-SAME: (float nofpclass(nan) [[ARG:%.*]]) #[[ATTR3]] {
+; TUNIT-SAME: (float nofpclass(nan inf) [[ARG:%.*]]) #[[ATTR3]] {
 ; TUNIT-NEXT:    [[RET:%.*]] = call float @llvm.arithmetic.fence.f32(float [[ARG]]) #[[ATTR18]]
 ; TUNIT-NEXT:    ret float [[RET]]
 ;
 ; CGSCC: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
 ; CGSCC-LABEL: define internal float @returns_fence
 ; CGSCC-SAME: (float nofpclass(nan inf) [[ARG:%.*]]) #[[ATTR3]] {
 ; CGSCC-NEXT:    [[RET:%.*]] = call float @llvm.arithmetic.fence.f32(float nofpclass(nan inf) [[ARG]]) #[[ATTR15]]
 ; CGSCC-NEXT:    ret float [[RET]]
 ;
   %ret = call float @llvm.arithmetic.fence.f32(float %arg)
   ret float %ret
 }
 
 ; Check that the func0 callsite is marked with both no inf and no nan
 define internal float @refine_callsite_attribute(float nofpclass(inf) %arg) {
 ; TUNIT: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
 ; TUNIT-LABEL: define internal float @refine_callsite_attribute
 ; TUNIT-SAME: (float nofpclass(inf) [[ARG:%.*]]) #[[ATTR3]] {
-; TUNIT-NEXT:    [[FUNC0:%.*]] = call float @returns_fence(float nofpclass(nan) [[ARG]]) #[[ATTR15]]
+; TUNIT-NEXT:    [[FUNC0:%.*]] = call float @returns_fence(float nofpclass(nan inf) [[ARG]]) #[[ATTR15]]
 ; TUNIT-NEXT:    [[RET:%.*]] = call float @llvm.arithmetic.fence.f32(float [[FUNC0]]) #[[ATTR18]]
 ; TUNIT-NEXT:    ret float [[RET]]
 ;
 ; CGSCC: Function Attrs: mustprogress nofree nosync nounwind willreturn memory(none)
 ; CGSCC-LABEL: define internal float @refine_callsite_attribute
 ; CGSCC-SAME: (float nofpclass(inf) [[ARG:%.*]]) #[[ATTR4]] {
 ; CGSCC-NEXT:    [[FUNC0:%.*]] = call float @returns_fence(float nofpclass(nan inf) [[ARG]]) #[[ATTR15]]
 ; CGSCC-NEXT:    [[RET:%.*]] = call float @llvm.arithmetic.fence.f32(float [[FUNC0]]) #[[ATTR15]]