[BuildLibCalls] Add nounwind,willreturn to memset_pattern{4,8,16}.

[fhahn]

Summary

Similar to memset, memset_pattern{4,8,16} all will return and do not
unwind. Use fallthrough to include all attributes also set for memset.

[fhahn]

rebase on top of precommitted test

[fhahn]

ping :)

[nikic]

LGTM

llvm/lib/Transforms/Utils/BuildLibCalls.cpp

case LibFunc_gettimeofday:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     return Changed;
   case LibFunc_memset_pattern4:
   case LibFunc_memset_pattern8:
   case LibFunc_memset_pattern16:
-    Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setDoesNotCapture(F, 0);
-    Changed |= setOnlyWritesMemory(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    LLVM_FALLTHROUGH;
   case LibFunc_memset:
     Changed |= setWillReturn(F);
     LLVM_FALLTHROUGH;
   case LibFunc_memset_chk:
     Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setOnlyWritesMemory(F, 0);
     Changed |= setDoesNotThrow(F);
     return Changed;

llvm/test/Transforms/DeadStoreElimination/libcalls-darwin.ll

 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -mtriple=x86_64-apple-macosx10.7 -passes=inferattrs,dse -S %s | FileCheck %s
 
 ; Tests for libcalls only available on Darwin platforms.
 
 declare void @memset_pattern4(i8*, i8*, i64)
 declare void @memset_pattern8(i8*, i8*, i64)
 declare void @memset_pattern16(i8*, i8*, i64)
 
 define void @test_memset_pattern4_const_size(i8* noalias %a, i8* noalias %pattern) {
 ; CHECK-LABEL: @test_memset_pattern4_const_size(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A_GEP_1:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 1
-; CHECK-NEXT:    store i8 0, i8* [[A_GEP_1]], align 1
-; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A]], i32 17
+; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 17
 ; CHECK-NEXT:    store i8 1, i8* [[A_GEP_17]], align 1
 ; CHECK-NEXT:    call void @memset_pattern4(i8* [[A]], i8* [[PATTERN:%.*]], i64 17)
 ; CHECK-NEXT:    ret void
 ;
 entry:
   %a.gep.1 = getelementptr i8, i8* %a, i32 1
   store i8 0, i8* %a.gep.1
   %a.gep.17 = getelementptr i8, i8* %a, i32 17
entry:
   store i8 1, i8* %a.gep.17
   call void @memset_pattern4(i8* %a, i8* %pattern, i64 %n)
   ret void
 }
 
 define void @test_memset_pattern8_const_size(i8* noalias %a, i8* noalias %pattern) {
 ; CHECK-LABEL: @test_memset_pattern8_const_size(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A_GEP_1:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 1
-; CHECK-NEXT:    store i8 0, i8* [[A_GEP_1]], align 1
-; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A]], i32 17
+; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 17
 ; CHECK-NEXT:    store i8 1, i8* [[A_GEP_17]], align 1
 ; CHECK-NEXT:    call void @memset_pattern8(i8* [[A]], i8* [[PATTERN:%.*]], i64 17)
 ; CHECK-NEXT:    ret void
 ;
 entry:
   %a.gep.1 = getelementptr i8, i8* %a, i32 1
   store i8 0, i8* %a.gep.1
   %a.gep.17 = getelementptr i8, i8* %a, i32 17
entry:
   store i8 1, i8* %a.gep.17
   call void @memset_pattern8(i8* %a, i8* %pattern, i64 %n)
   ret void
 }
 
 define void @test_memset_pattern16_const_size(i8* noalias %a, i8* noalias %pattern) {
 ; CHECK-LABEL: @test_memset_pattern16_const_size(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[A_GEP_1:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 1
-; CHECK-NEXT:    store i8 0, i8* [[A_GEP_1]], align 1
-; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A]], i32 17
+; CHECK-NEXT:    [[A_GEP_17:%.*]] = getelementptr i8, i8* [[A:%.*]], i32 17
 ; CHECK-NEXT:    store i8 1, i8* [[A_GEP_17]], align 1
 ; CHECK-NEXT:    call void @memset_pattern16(i8* [[A]], i8* [[PATTERN:%.*]], i64 17)
 ; CHECK-NEXT:    ret void
 ;
 entry:
   %a.gep.1 = getelementptr i8, i8* %a, i32 1
   store i8 0, i8* %a.gep.1
   %a.gep.17 = getelementptr i8, i8* %a, i32 17

llvm/test/Transforms/InferFunctionAttrs/annotate.ll

 ; CHECK: declare noundef i32 @vsscanf(i8* nocapture noundef readonly, i8* nocapture noundef readonly, %opaque* noundef) [[NOFREE_NOUNWIND]]
 declare i32 @vsscanf(i8*, i8*, %opaque*)
 
 ; CHECK: declare noundef i64 @write(i32 noundef, i8* nocapture noundef readonly, i64 noundef) [[NOFREE]]
 declare i64 @write(i32, i8*, i64)
 
 
 ; memset_pattern{4,8,16} aren't available everywhere.
-; CHECK-DARWIN: declare void @memset_pattern4(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE:#[0-9]+]]
+; CHECK-DARWIN: declare void @memset_pattern4(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN]]
 declare void @memset_pattern4(i8*, i8*, i64)
-; CHECK-DARWIN: declare void @memset_pattern8(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE]]
+; CHECK-DARWIN: declare void @memset_pattern8(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN]]
 declare void @memset_pattern8(i8*, i8*, i64)
-; CHECK-DARWIN: declare void @memset_pattern16(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE]]
+; CHECK-DARWIN: declare void @memset_pattern16(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN]]
 declare void @memset_pattern16(i8*, i8*, i64)
 
 
 ; CHECK-DAG: attributes [[NOFREE_NOUNWIND_WILLRETURN]] = { mustprogress nofree nounwind willreturn }
 ; CHECK-DAG: attributes [[NOFREE_NOUNWIND_WILLRETURN_WRITEONLY]] = { mustprogress nofree nounwind willreturn writeonly }
 ; CHECK-DAG: attributes [[NOFREE_NOUNWIND]] = { nofree nounwind }
 ; CHECK-DAG: attributes [[INACCESSIBLEMEMONLY_NOFREE_NOUNWIND_WILLRETURN]] = { inaccessiblememonly mustprogress nofree nounwind willreturn }
 ; CHECK-DAG: attributes [[NOFREE_NOUNWIND_READONLY_WILLRETURN]] = { mustprogress nofree nounwind readonly willreturn }
 ; CHECK-DAG: attributes [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN]] = { argmemonly mustprogress nofree nounwind willreturn }
 ; CHECK-DAG: attributes [[NOFREE_NOUNWIND_READONLY]] = { nofree nounwind readonly }
 ; CHECK-DAG: attributes [[INACCESSIBLEMEMORARGMEMONLY_NOUNWIND_WILLRETURN]] = { inaccessiblemem_or_argmemonly mustprogress nounwind willreturn }
 ; CHECK-DAG: attributes [[NOFREE_WILLRETURN]] = { mustprogress nofree willreturn }
 ; CHECK-DAG: attributes [[ARGMEMONLY_NOFREE_NOUNWIND_READONLY_WILLRETURN]] = { argmemonly mustprogress nofree nounwind readonly willreturn }
 ; CHECK-DAG: attributes [[NOFREE]] = { nofree }
 ; CHECK-DAG: attributes [[INACCESSIBLEMEMORARGONLY_NOFREE_NOUNWIND_WILLRETURN]]  = { inaccessiblemem_or_argmemonly mustprogress nofree nounwind willreturn }
 ; CHECK-DAG: attributes [[ARGMEMONLY_NOFREE_NOUNWIND]] = { argmemonly nofree nounwind }
 
-; CHECK-DARWIN-DAG: attributes [[ARGMEMONLY_NOFREE]] = { argmemonly nofree }
 ; CHECK-NVPTX-DAG: attributes [[NOFREE_NOUNWIND_READNONE]] = { nofree nosync nounwind readnone }