Extend 'readonly' and 'readnone' to work on function arguments as well as
functions. Make the function attributes pass add it to known library functions
and when it can deduce it.

llvm-svn: 185735
diff --git a/llvm/test/Transforms/FunctionAttrs/nocapture.ll b/llvm/test/Transforms/FunctionAttrs/nocapture.ll
index 3027acd..110bd03 100644
--- a/llvm/test/Transforms/FunctionAttrs/nocapture.ll
+++ b/llvm/test/Transforms/FunctionAttrs/nocapture.ll
@@ -1,12 +1,13 @@
 ; RUN: opt < %s -functionattrs -S | FileCheck %s
 @g = global i32* null		; <i32**> [#uses=1]
 
-; CHECK: define i32* @c1(i32* %q)
+; CHECK: define i32* @c1(i32* readnone %q)
 define i32* @c1(i32* %q) {
 	ret i32* %q
 }
 
 ; CHECK: define void @c2(i32* %q)
+; It would also be acceptable to mark %q as readnone. Update @c3 too.
 define void @c2(i32* %q) {
 	store i32* %q, i32** @g
 	ret void
@@ -45,7 +46,7 @@
 
 declare void @throw_if_bit_set(i8*, i8) readonly
 
-; CHECK: define i1 @c6(i8* %q, i8 %bit)
+; CHECK: define i1 @c6(i8* readonly %q, i8 %bit)
 define i1 @c6(i8* %q, i8 %bit) {
 	invoke void @throw_if_bit_set(i8* %q, i8 %bit)
 		to label %ret0 unwind label %ret1
@@ -67,7 +68,7 @@
 	ret i1* %lookup
 }
 
-; CHECK: define i1 @c7(i32* %q, i32 %bitno)
+; CHECK: define i1 @c7(i32* readnone %q, i32 %bitno)
 define i1 @c7(i32* %q, i32 %bitno) {
 	%ptr = call i1* @lookup_bit(i32* %q, i32 %bitno)
 	%val = load i1* %ptr
@@ -103,7 +104,7 @@
 }
 
 declare void @external(i8*) readonly nounwind
-; CHECK: define void @nc4(i8* nocapture %p)
+; CHECK: define void @nc4(i8* nocapture readonly %p)
 define void @nc4(i8* %p) {
 	call void @external(i8* %p)
 	ret void
@@ -116,28 +117,29 @@
 	ret void
 }
 
-; CHECK: define void @test1_1(i8* nocapture %x1_1, i8* %y1_1)
+; CHECK: define void @test1_1(i8* nocapture readnone %x1_1, i8* %y1_1)
+; It would be acceptable to add readnone to %y1_1 and %y1_2.
 define void @test1_1(i8* %x1_1, i8* %y1_1) {
   call i8* @test1_2(i8* %x1_1, i8* %y1_1)
   store i32* null, i32** @g
   ret void
 }
 
-; CHECK: define i8* @test1_2(i8* nocapture %x1_2, i8* %y1_2)
+; CHECK: define i8* @test1_2(i8* nocapture readnone %x1_2, i8* %y1_2)
 define i8* @test1_2(i8* %x1_2, i8* %y1_2) {
   call void @test1_1(i8* %x1_2, i8* %y1_2)
   store i32* null, i32** @g
   ret i8* %y1_2
 }
 
-; CHECK: define void @test2(i8* nocapture %x2)
+; CHECK: define void @test2(i8* nocapture readnone %x2)
 define void @test2(i8* %x2) {
   call void @test2(i8* %x2)
   store i32* null, i32** @g
   ret void
 }
 
-; CHECK: define void @test3(i8* nocapture %x3, i8* nocapture %y3, i8* nocapture %z3)
+; CHECK: define void @test3(i8* nocapture readnone %x3, i8* nocapture readnone %y3, i8* nocapture readnone %z3)
 define void @test3(i8* %x3, i8* %y3, i8* %z3) {
   call void @test3(i8* %z3, i8* %y3, i8* %x3)
   store i32* null, i32** @g
@@ -151,7 +153,7 @@
   ret void
 }
 
-; CHECK: define i8* @test4_2(i8* nocapture %x4_2, i8* %y4_2, i8* nocapture %z4_2)
+; CHECK: define i8* @test4_2(i8* nocapture readnone %x4_2, i8* readnone %y4_2, i8* nocapture readnone %z4_2)
 define i8* @test4_2(i8* %x4_2, i8* %y4_2, i8* %z4_2) {
   call void @test4_1(i8* null)
   store i32* null, i32** @g