BuildLibCalls: simplify switch statement slightly

[durin42]

Summary

Per feedback on D123086 after submit.

Also added a test for vec_malloc et al attribute inference to show it's
doing the right thing.

The new tests exposed a defect, corrected by adding vec_free to the list of
free functions in MemoryBuiltins.cpp, which had been overlooked all the
way back in D94710, over a year ago.

[nikic]

llvm/lib/Transforms/Utils/BuildLibCalls.cpp

447

Can you please also update the similar vec_realloc/vec_calloc/vec_free cases?

[nikic]

LGTM

llvm/lib/Transforms/Utils/BuildLibCalls.cpp

case LibFunc_system:
     Changed |= setOnlyReadsMemory(F, 0);
     return Changed;
   case LibFunc_aligned_alloc:
     Changed |= setAlignedAllocParam(F, 0);
     Changed |= setAllocSize(F, 1, None);
     LLVM_FALLTHROUGH;
   case LibFunc_valloc:
   case LibFunc_malloc:
-    Changed |= setAllocFamily(F, "malloc");
-    LLVM_FALLTHROUGH;
   case LibFunc_vec_malloc:
-    Changed |= setAllocFamily(F, "vec_malloc");
+    Changed |= setAllocFamily(F, TheLibFunc == LibFunc_vec_malloc ? "vec_malloc" : "malloc");
     Changed |= setAllocSize(F, 0, None);
     Changed |= setOnlyAccessesInaccessibleMemory(F);
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setWillReturn(F);
     return Changed;
   case LibFunc_memcmp:
     Changed |= setOnlyAccessesArgMemory(F);

llvm/test/Transforms/InferFunctionAttrs/annotate.ll

 ; RUN: opt < %s -mtriple=x86_64-- -inferattrs -S | FileCheck --match-full-lines --check-prefixes=CHECK,CHECK-NOLINUX,CHECK-OPEN,CHECK-UNKNOWN %s
 ; RUN: opt < %s -mtriple=x86_64-- -passes=inferattrs -S | FileCheck --match-full-lines --check-prefixes=CHECK,CHECK-NOLINUX,CHECK-OPEN,CHECK-UNKNOWN %s
 ; RUN: opt < %s -mtriple=x86_64-apple-macosx10.8.0 -inferattrs -S | FileCheck --match-full-lines --check-prefixes=CHECK,CHECK-KNOWN,CHECK-NOLINUX,CHECK-OPEN,CHECK-DARWIN %s
 ; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -inferattrs -S | FileCheck --match-full-lines --check-prefixes=CHECK,CHECK-KNOWN,CHECK-LINUX %s
 ; RUN: opt < %s -mtriple=nvptx -inferattrs -S | FileCheck --match-full-lines --check-prefixes=CHECK-NOLINUX,CHECK-NVPTX %s
+; RUN: opt < %s -mtriple=powerpc-ibm-aix-xcoff -inferattrs -S | FileCheck --match-full-lines --check-prefixes=CHECK-AIX %s
 
 declare i32 @__nvvm_reflect(i8*)
 ; CHECK-NVPTX: declare noundef i32 @__nvvm_reflect(i8* noundef) [[NOFREE_NOUNWIND_READNONE:#[0-9]+]]
 
 
 ; Check all the libc functions (thereby also exercising the prototype check).
 ; Note that it's OK to modify these as attributes might be missing. These checks
 ; reflect the currently inferred attributes.

 declare i32 @lstat(i8*, %opaque*)
 
 ; CHECK-LINUX: declare noundef i32 @lstat64(i8* nocapture noundef readonly, %opaque* nocapture noundef) [[NOFREE_NOUNWIND]]
 declare i32 @lstat64(i8*, %opaque*)
 
 ; CHECK: declare noalias noundef i8* @malloc(i64 noundef) [[INACCESSIBLEMEMONLY_NOFREE_NOUNWIND_WILLRETURN_ALLOCSIZE0_FAMILY_MALLOC:#[0-9]+]]
 declare i8* @malloc(i64)
 
+; CHECK-AIX: declare noalias noundef i8* @vec_malloc(i64 noundef) [[INACCESSIBLEMEMONLY_NOFREE_NOUNWIND_WILLRETURN_ALLOCSIZE0_FAMILY_VEC_MALLOC:#[0-9]+]]
+declare i8* @vec_malloc(i64)
+
 ; CHECK-LINUX: declare noalias noundef i8* @memalign(i64 allocalign, i64) [[INACCESSIBLEMEMONLY_NOFREE_NOUNWIND_WILLRETURN:#[0-9]+]]
 declare i8* @memalign(i64, i64)
 
 ; CHECK: declare i8* @memccpy(i8* noalias writeonly, i8* noalias nocapture readonly, i32, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_WILLRETURN]]
 declare i8* @memccpy(i8*, i8*, i32, i64)
 
 ; CHECK-LINUX:   declare i8* @memchr(i8*, i32, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_READONLY]]
 ; CHECK-DARWIN:  declare i8* @memchr(i8*, i32, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_READONLY:#[0-9]+]]

 ; CHECK-DAG: attributes [[INACCESSIBLEMEMONLY_NOFREE_NOUNWIND_WILLRETURN_ALLOCSIZE0_FAMILY_MALLOC]] = { inaccessiblememonly mustprogress nofree nounwind willreturn allocsize(0) "alloc-family"="malloc" }
 ; CHECK-DAG: attributes [[ARGMEMONLY_NOFREE_NOUNWIND_READONLY_WILLRETURN]] = { argmemonly mustprogress nofree nounwind readonly willreturn }
 ; CHECK-DAG: attributes [[NOFREE]] = { nofree }
 ; CHECK-DAG: attributes [[ARGMEMONLY_NOFREE_NOUNWIND]] = { argmemonly nofree nounwind }
 ; CHECK-DAG: attributes [[INACCESSIBLEMEMORARGMEMONLY_NOUNWIND_WILLRETURN_ALLOCSIZE_FAMILY_MALLOC]] = { inaccessiblemem_or_argmemonly mustprogress nounwind willreturn allocsize(1) "alloc-family"="malloc" }
 ; CHECK-DAG: attributes [[INACCESSIBLEMEMORARGONLY_NOFREE_NOUNWIND_WILLRETURN_FAMILY_MALLOC]] = { inaccessiblemem_or_argmemonly mustprogress nofree nounwind willreturn "alloc-family"="malloc" }
 
 ; CHECK-NVPTX-DAG: attributes [[NOFREE_NOUNWIND_READNONE]] = { nofree nosync nounwind readnone }
+
+; CHECK-AIX-DAG: attributes [[INACCESSIBLEMEMONLY_NOFREE_NOUNWIND_WILLRETURN_ALLOCSIZE0_FAMILY_VEC_MALLOC]] = { inaccessiblememonly mustprogress nofree nounwind willreturn allocsize(0) "alloc-family"="vec_malloc" }