diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -270,9 +270,6 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
 
   bool Changed = false;
 
-  if(!isLibFreeFunction(&F, TheLibFunc) && !isReallocLikeFn(&F,  &TLI))
-    Changed |= setDoesNotFreeMemory(F);
-
   if (F.getParent() != nullptr && F.getParent()->getRtLibUseGOT())
     Changed |= setNonLazyBind(F);
 
@@ -285,14 +282,14 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_strchr:
   case LibFunc_strrchr:
     Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
-    return Changed;
+    break;
   case LibFunc_strtol:
   case LibFunc_strtod:
   case LibFunc_strtof:
@@ -304,7 +301,7 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_strcat:
   case LibFunc_strncat:
     Changed |= setOnlyAccessesArgMemory(F);
@@ -315,7 +312,7 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setOnlyReadsMemory(F, 1);
     Changed |= setDoesNotAlias(F, 0);
     Changed |= setDoesNotAlias(F, 1);
-    return Changed;
+    break;
   case LibFunc_strcpy:
   case LibFunc_strncpy:
     Changed |= setReturnedArg(F, 0);
@@ -330,14 +327,14 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setOnlyReadsMemory(F, 1);
     Changed |= setDoesNotAlias(F, 0);
     Changed |= setDoesNotAlias(F, 1);
-    return Changed;
+    break;
   case LibFunc_strxfrm:
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_strcmp:      // 0,1
   case LibFunc_strspn:      // 0,1
   case LibFunc_strncmp:     // 0,1
@@ -348,7 +345,7 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_strcoll:
   case LibFunc_strcasecmp:  // 0,1
   case LibFunc_strncasecmp: //
@@ -359,34 +356,34 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_strstr:
   case LibFunc_strpbrk:
     Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_strtok:
   case LibFunc_strtok_r:
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_scanf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_setbuf:
   case LibFunc_setvbuf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_strndup:
     Changed |= setArgNoUndef(F, 1);
     LLVM_FALLTHROUGH;
@@ -398,23 +395,23 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_stat:
   case LibFunc_statvfs:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_sscanf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_sprintf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
@@ -423,7 +420,7 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setOnlyWritesMemory(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_snprintf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
@@ -432,21 +429,21 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setOnlyWritesMemory(F, 0);
     Changed |= setDoesNotCapture(F, 2);
     Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
+    break;
   case LibFunc_setitimer:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setDoesNotCapture(F, 2);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_system:
     // May throw; "system" is a valid pthread cancellation point.
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_aligned_alloc:
     Changed |= setAlignedAllocParam(F, 0);
     Changed |= setAllocSize(F, 1, None);
@@ -464,29 +461,29 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setWillReturn(F);
-    return Changed;
+    break;
   case LibFunc_memcmp:
     Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_memchr:
   case LibFunc_memrchr:
     Changed |= setDoesNotThrow(F);
     Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setOnlyReadsMemory(F);
     Changed |= setWillReturn(F);
-    return Changed;
+    break;
   case LibFunc_modf:
   case LibFunc_modff:
   case LibFunc_modfl:
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_memcpy:
     Changed |= setDoesNotThrow(F);
     Changed |= setOnlyAccessesArgMemory(F);
@@ -497,7 +494,7 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotAlias(F, 1);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_memmove:
     Changed |= setDoesNotThrow(F);
     Changed |= setOnlyAccessesArgMemory(F);
@@ -506,7 +503,7 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setOnlyWritesMemory(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_mempcpy:
   case LibFunc_memccpy:
     Changed |= setWillReturn(F);
@@ -519,7 +516,7 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotAlias(F, 1);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_memalign:
     Changed |= setAllocFamily(F, "malloc");
     Changed |= setAllocKind(F, AllocFnKind::Alloc | AllocFnKind::Aligned |
@@ -531,19 +528,19 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setWillReturn(F);
-    return Changed;
+    break;
   case LibFunc_mkdir:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_mktime:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_realloc:
   case LibFunc_reallocf:
   case LibFunc_vec_realloc:
@@ -559,46 +556,46 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setArgNoUndef(F, 1);
-    return Changed;
+    break;
   case LibFunc_read:
     // May throw; "read" is a valid pthread cancellation point.
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_rewind:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_rmdir:
   case LibFunc_remove:
   case LibFunc_realpath:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_rename:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_readlink:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_write:
     // May throw; "write" is a valid pthread cancellation point.
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_bcopy:
     Changed |= setDoesNotThrow(F);
     Changed |= setOnlyAccessesArgMemory(F);
@@ -607,22 +604,22 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyWritesMemory(F, 1);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_bcmp:
     Changed |= setDoesNotThrow(F);
     Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setOnlyReadsMemory(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_bzero:
     Changed |= setDoesNotThrow(F);
     Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyWritesMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_calloc:
   case LibFunc_vec_calloc:
     Changed |= setAllocFamily(F, TheLibFunc == LibFunc_vec_calloc ? "vec_malloc"
@@ -634,21 +631,21 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setWillReturn(F);
-    return Changed;
+    break;
   case LibFunc_chmod:
   case LibFunc_chown:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_ctermid:
   case LibFunc_clearerr:
   case LibFunc_closedir:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_atoi:
   case LibFunc_atol:
   case LibFunc_atof:
@@ -657,13 +654,13 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setOnlyReadsMemory(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_access:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_fopen:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
@@ -672,19 +669,19 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_fdopen:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_feof:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_free:
   case LibFunc_vec_free:
     Changed |= setAllocFamily(F, TheLibFunc == LibFunc_vec_free ? "vec_malloc"
@@ -696,7 +693,7 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_fseek:
   case LibFunc_ftell:
   case LibFunc_fgetc:
@@ -713,135 +710,135 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_ferror:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F);
-    return Changed;
+    break;
   case LibFunc_fputc:
   case LibFunc_fputc_unlocked:
   case LibFunc_fstat:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_frexp:
   case LibFunc_frexpf:
   case LibFunc_frexpl:
     Changed |= setDoesNotThrow(F);
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_fstatvfs:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_fgets:
   case LibFunc_fgets_unlocked:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 2);
-    return Changed;
+    break;
   case LibFunc_fread:
   case LibFunc_fread_unlocked:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 3);
-    return Changed;
+    break;
   case LibFunc_fwrite:
   case LibFunc_fwrite_unlocked:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 3);
     // FIXME: readonly #1?
-    return Changed;
+    break;
   case LibFunc_fputs:
   case LibFunc_fputs_unlocked:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_fscanf:
   case LibFunc_fprintf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_fgetpos:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_getc:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_getlogin_r:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_getc_unlocked:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_getenv:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_gets:
   case LibFunc_getchar:
   case LibFunc_getchar_unlocked:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
-    return Changed;
+    break;
   case LibFunc_getitimer:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_getpwnam:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_ungetc:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_uname:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_unlink:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_unsetenv:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_utime:
   case LibFunc_utimes:
     Changed |= setRetAndArgsNoUndef(F);
@@ -850,37 +847,37 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_putc:
   case LibFunc_putc_unlocked:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_puts:
   case LibFunc_printf:
   case LibFunc_perror:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_pread:
     // May throw; "pread" is a valid pthread cancellation point.
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_pwrite:
     // May throw; "pwrite" is a valid pthread cancellation point.
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_putchar:
   case LibFunc_putchar_unlocked:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
-    return Changed;
+    break;
   case LibFunc_popen:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
@@ -889,103 +886,103 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_pclose:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_vscanf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_vsscanf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_vfscanf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_vprintf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_vfprintf:
   case LibFunc_vsprintf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_vsnprintf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 2);
     Changed |= setOnlyReadsMemory(F, 2);
-    return Changed;
+    break;
   case LibFunc_open:
     // May throw; "open" is a valid pthread cancellation point.
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_opendir:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_tmpfile:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
-    return Changed;
+    break;
   case LibFunc_times:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_htonl:
   case LibFunc_htons:
   case LibFunc_ntohl:
   case LibFunc_ntohs:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotAccessMemory(F);
-    return Changed;
+    break;
   case LibFunc_lstat:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_lchown:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_qsort:
     // May throw; places call through function pointer.
     // Cannot give undef pointer/size
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 3);
-    return Changed;
+    break;
   case LibFunc_dunder_strndup:
     Changed |= setArgNoUndef(F, 1);
     LLVM_FALLTHROUGH;
@@ -995,28 +992,28 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setWillReturn(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_dunder_strtok_r:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_under_IO_getc:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_under_IO_putc:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_dunder_isoc99_scanf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_stat64:
   case LibFunc_lstat64:
   case LibFunc_statvfs64:
@@ -1025,15 +1022,15 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_dunder_isoc99_sscanf:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_fopen64:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
@@ -1042,30 +1039,30 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 0);
     Changed |= setOnlyReadsMemory(F, 1);
-    return Changed;
+    break;
   case LibFunc_fseeko64:
   case LibFunc_ftello64:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
-    return Changed;
+    break;
   case LibFunc_tmpfile64:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setRetDoesNotAlias(F);
-    return Changed;
+    break;
   case LibFunc_fstat64:
   case LibFunc_fstatvfs64:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_open64:
     // May throw; "open" is a valid pthread cancellation point.
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setOnlyReadsMemory(F, 0);
-    return Changed;
+    break;
   case LibFunc_gettimeofday:
     // Currently some platforms have the restrict keyword on the arguments to
     // gettimeofday. To be conservative, do not add noalias to gettimeofday's
@@ -1074,7 +1071,7 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
     Changed |= setDoesNotCapture(F, 1);
-    return Changed;
+    break;
   case LibFunc_memset_pattern4:
   case LibFunc_memset_pattern8:
   case LibFunc_memset_pattern16:
@@ -1089,18 +1086,18 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setOnlyAccessesArgMemory(F);
     Changed |= setOnlyWritesMemory(F, 0);
     Changed |= setDoesNotThrow(F);
-    return Changed;
+    break;
   // int __nvvm_reflect(const char *)
   case LibFunc_nvvm_reflect:
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotAccessMemory(F);
     Changed |= setDoesNotThrow(F);
-    return Changed;
+    break;
   case LibFunc_ldexp:
   case LibFunc_ldexpf:
   case LibFunc_ldexpl:
     Changed |= setWillReturn(F);
-    return Changed;
+    break;
   case LibFunc_abs:
   case LibFunc_acos:
   case LibFunc_acosf:
@@ -1227,12 +1224,17 @@ bool llvm::inferNonMandatoryLibFuncAttrs(Function &F,
     Changed |= setDoesNotFreeMemory(F);
     Changed |= setOnlyWritesMemory(F);
     Changed |= setWillReturn(F);
-    return Changed;
+    break;
   default:
     // FIXME: It'd be really nice to cover all the library functions we're
     // aware of here.
-    return false;
+    break;
   }
+  // We have to do this step after AllocKind has been inferred on functions so
+  // we can reliably identify free-like and realloc-like functions.
+  if (!isLibFreeFunction(&F, TheLibFunc) && !isReallocLikeFn(&F, &TLI))
+    Changed |= setDoesNotFreeMemory(F);
+  return Changed;
 }
 
 static void setArgExtAttr(Function &F, unsigned ArgNo,

diff --git a/llvm/test/Transforms/InstCombine/out-of-tree-allocator-optimizes-away.ll b/llvm/test/Transforms/InstCombine/out-of-tree-allocator-optimizes-away.ll
@@ -0,0 +1,18 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -passes=instcombine %s | FileCheck %s
+
+; Function Attrs: nonlazybind uwtable
+define void @alloc_elides_test(i32 %data){
+; CHECK-LABEL: @alloc_elides_test(
+; CHECK-NEXT:  start:
+; CHECK-NEXT:    ret void
+;
+start:
+  %0 = tail call i8* @__rust_alloc(i64 4, i64 32)
+  tail call void @__rust_dealloc(i8* nonnull %0, i64 4, i64 32)
+  ret void
+}
+
+declare noalias i8* @__rust_alloc(i64, i64 allocalign) unnamed_addr nounwind nonlazybind allocsize(0) uwtable allockind("alloc,uninitialized,aligned") "alloc-family"="__rust_alloc"
+
+declare void @__rust_dealloc(i8* allocptr, i64, i64) unnamed_addr nounwind nonlazybind uwtable allockind("free") "alloc-family"="__rust_alloc"