[Attributor] Teach AANoCapture to use information in-flight more aggressively

AAReturnedValues, AAMemoryBehavior, and AANoUnwind, can provide
information that helps during the tracking or even justifies no-capture.
We now use this information and enable no-capture in some test cases
designed a long while a ago for these cases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375382 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/FunctionAttrs/arg_nocapture.ll

@@ -405,35 +405,33 @@ entry:
 ;
 ; Make sure the returned flag on %r is strong enough to justify nocapture on %b but **not** on %r.
 ;
-; FIXME: The "returned" information is not propagated to the fullest extend causing us to miss "nocapture" on %b in the following:
-; CHECK: define i32* @not_captured_by_readonly_call_not_returned_either1(i32* readonly %b, i32* readonly returned %r)
+; CHECK: define i32* @not_captured_by_readonly_call_not_returned_either1(i32* nocapture readonly %b, i32* readonly returned %r)
 ;
-; CHECK: define i32* @not_captured_by_readonly_call_not_returned_either2(i32* readonly %b, i32* readonly returned %r)
-; CHECK: define i32* @not_captured_by_readonly_call_not_returned_either3(i32* readonly %b, i32* readonly returned %r)
+; CHECK: define i32* @not_captured_by_readonly_call_not_returned_either2(i32* nocapture readonly %b, i32* readonly returned %r)
+; CHECK: define i32* @not_captured_by_readonly_call_not_returned_either3(i32* nocapture readonly %b, i32* readonly returned %r)
 ;
-; FIXME: The "nounwind" information is not derived to the fullest extend causing us to miss "nocapture" on %b in the following:
-; CHECK: define i32* @not_captured_by_readonly_call_not_returned_either4(i32* readonly %b, i32* readonly returned %r)
-define i32* @not_captured_by_readonly_call_not_returned_either1(i32* %b, i32* returned %r) #0 {
+; CHECK: define i32* @not_captured_by_readonly_call_not_returned_either4(i32* nocapture readonly %b, i32* readonly returned %r)
+define i32* @not_captured_by_readonly_call_not_returned_either1(i32* %b, i32* returned %r) {
 entry:
   %call = call i32* @readonly_unknown(i32* %b, i32* %r) nounwind
   ret i32* %call
 }
 
 declare i32* @readonly_unknown_r1a(i32*, i32* returned) readonly
-define i32* @not_captured_by_readonly_call_not_returned_either2(i32* %b, i32* %r) #0 {
+define i32* @not_captured_by_readonly_call_not_returned_either2(i32* %b, i32* %r) {
 entry:
   %call = call i32* @readonly_unknown_r1a(i32* %b, i32* %r) nounwind
   ret i32* %call
 }
 
 declare i32* @readonly_unknown_r1b(i32*, i32* returned) readonly nounwind
-define i32* @not_captured_by_readonly_call_not_returned_either3(i32* %b, i32* %r) #0 {
+define i32* @not_captured_by_readonly_call_not_returned_either3(i32* %b, i32* %r) {
 entry:
   %call = call i32* @readonly_unknown_r1b(i32* %b, i32* %r)
   ret i32* %call
 }
 
-define i32* @not_captured_by_readonly_call_not_returned_either4(i32* %b, i32* %r) #0 {
+define i32* @not_captured_by_readonly_call_not_returned_either4(i32* %b, i32* %r) nounwind {
 entry:
   %call = call i32* @readonly_unknown_r1a(i32* %b, i32* %r)
   ret i32* %call

test/Transforms/FunctionAttrs/arg_returned.ll

@@ -1,5 +1,5 @@
 ; RUN: opt -functionattrs -S < %s | FileCheck %s --check-prefix=FNATTR
-; RUN: opt -attributor -attributor-manifest-internal -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=6 -S < %s | FileCheck %s --check-prefix=ATTRIBUTOR
+; RUN: opt -attributor -attributor-manifest-internal -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=7 -S < %s | FileCheck %s --check-prefix=ATTRIBUTOR
 ; RUN: opt -attributor -attributor-manifest-internal -attributor-disable=false -functionattrs -S < %s | FileCheck %s --check-prefix=BOTH
 ;
 ; Test cases specifically designed for the "returned" argument attribute.

test/Transforms/FunctionAttrs/nocapture.ll

@@ -39,6 +39,20 @@ l1:
 	ret i1 1 ; escaping value not caught by def-use chaining.
 }
 
+; c4b is c4 but without the escaping part
+; FNATTR: define i1 @c4b(i32* %q, i32 %bitno)
+; ATTRIBUTOR: define i1 @c4b(i32* nocapture readnone %q, i32 %bitno)
+define i1 @c4b(i32* %q, i32 %bitno) {
+	%tmp = ptrtoint i32* %q to i32
+	%tmp2 = lshr i32 %tmp, %bitno
+	%bit = trunc i32 %tmp2 to i1
+	br i1 %bit, label %l1, label %l0
+l0:
+	ret i1 0 ; not escaping!
+l1:
+	ret i1 0 ; not escaping!
+}
+
 @lookup_table = global [2 x i1] [ i1 0, i1 1 ]
 
 ; FNATTR: define i1 @c5(i32* %q, i32 %bitno)
@@ -331,5 +345,20 @@ entry:
   ret void
 }
 
+declare i8* @unknownpi8pi8(i8*,i8* returned)
+define i8* @test_returned1(i8* %A, i8* returned %B) nounwind readonly {
+; ATTRIBUTOR: define i8* @test_returned1(i8* nocapture readonly %A, i8* readonly returned %B)
+entry:
+  %p = call i8* @unknownpi8pi8(i8* %A, i8* %B)
+  ret i8* %p
+}
+
+define i8* @test_returned2(i8* %A, i8* %B) {
+; ATTRIBUTOR: define i8* @test_returned2(i8* nocapture readonly %A, i8* readonly returned %B)
+entry:
+  %p = call i8* @unknownpi8pi8(i8* %A, i8* %B) nounwind readonly
+  ret i8* %p
+}
+
 declare i8* @llvm.launder.invariant.group.p0i8(i8*)
 declare i8* @llvm.strip.invariant.group.p0i8(i8*)

test/Transforms/FunctionAttrs/nonnull.ll

@@ -220,7 +220,7 @@ bb:
 
 define dso_local noalias i32* @f3(i32* %arg) {
 ; FIXME: missing nonnull. It should be nonnull @f3(i32* nonnull readonly %arg) 
-; ATTRIBUTOR: define dso_local noalias i32* @f3(i32* readonly %arg)
+; ATTRIBUTOR: define dso_local noalias i32* @f3(i32* nocapture readonly %arg)
 bb:
 ; FIXME: missing nonnull. It should be @f1(i32* nonnull readonly %arg) 
 ; ATTRIBUTOR:   %tmp = call i32* @f1(i32* readonly %arg)

test/Transforms/FunctionAttrs/read_write_returned_arguments_scc.ll

@@ -1,4 +1,4 @@
-; RUN: opt -functionattrs -enable-nonnull-arg-prop -attributor -attributor-manifest-internal -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=7 -S < %s | FileCheck %s
+; RUN: opt -functionattrs -enable-nonnull-arg-prop -attributor -attributor-manifest-internal -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=8 -S < %s | FileCheck %s
 ;
 ; This is an evolved example to stress test SCC parameter attribute propagation.
 ; The SCC in this test is made up of the following six function, three of which