[ArgPromo][Tests] Examples to show missing 'byval' argument propagation

[jdoerfert]

Summary

This adds a test to show that we miss propagating a byval array.
Similar problem cases are already in the code base, see

https://bugs.llvm.org/show_bug.cgi?id=42852

[jdoerfert]

Fix check line placement

[jdoerfert]

I will propose more test improvements in a different review

[jdoerfert]

Add and improve more tests

[jdoerfert]

mixed up review numbers, abandon this one again

llvm/test/Transforms/ArgumentPromotion/byval.ll

 ; RUN: opt < %s -argpromotion -S | FileCheck %s
 ; RUN: opt < %s -passes=argpromotion -S | FileCheck %s
 
 target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
 
 %struct.ss = type { i32, i64 }
 
 define internal void @f(%struct.ss* byval  %b) nounwind  {
 entry:
+; CHECK-LABEL: define internal void @f(i32 %b.0, i64 %b.1)
+; CHECK: alloca %struct.ss{{$}}
+; CHECK: store i32 %b.0
+; CHECK: store i64 %b.1
   %tmp = getelementptr %struct.ss, %struct.ss* %b, i32 0, i32 0
   %tmp1 = load i32, i32* %tmp, align 4
   %tmp2 = add i32 %tmp1, 1
   store i32 %tmp2, i32* %tmp, align 4
   ret void
 }
 
-; CHECK-LABEL: define internal void @f(i32 %b.0, i64 %b.1)
-; CHECK: alloca %struct.ss{{$}}
-; CHECK: store i32 %b.0
-; CHECK: store i64 %b.1
-
 define internal void @g(%struct.ss* byval align 32 %b) nounwind {
 entry:
+
+; CHECK-LABEL: define internal void @g(i32 %b.0, i64 %b.1)
+; CHECK: alloca %struct.ss, align 32
+; CHECK: store i32 %b.0
+; CHECK: store i64 %b.1
   %tmp = getelementptr %struct.ss, %struct.ss* %b, i32 0, i32 0
   %tmp1 = load i32, i32* %tmp, align 4
   %tmp2 = add i32 %tmp1, 1
   store i32 %tmp2, i32* %tmp, align 4
   ret void
 }
 
-; CHECK-LABEL: define internal void @g(i32 %b.0, i64 %b.1)
-; CHECK: alloca %struct.ss, align 32
-; CHECK: store i32 %b.0
-; CHECK: store i64 %b.1
+define internal void @h([2 x i32]* byval %b) nounwind {
+entry:
+; Even if we do not access the first element we can promote this array.
+  %tmp = getelementptr [2 x i32], [2 x i32]* %b, i32 0, i32 1
+  %tmp1 = load i32, i32* %tmp, align 4
+  %tmp2 = add i32 %tmp1, 1
+  store i32 %tmp2, i32* %tmp, align 4
+  ret void
+}
 
 define i32 @main() nounwind  {
 entry:
+; CHECK-LABEL: define i32 @main
+  %A = alloca [2 x i32]
   %S = alloca %struct.ss
   %tmp1 = getelementptr %struct.ss, %struct.ss* %S, i32 0, i32 0
   store i32 1, i32* %tmp1, align 8
   %tmp4 = getelementptr %struct.ss, %struct.ss* %S, i32 0, i32 1
   store i64 2, i64* %tmp4, align 4
+
   call void @f(%struct.ss* byval %S) nounwind
+; CHECK: call void @f(i32 %{{.*}}, i64 %{{.*}})
+
   call void @g(%struct.ss* byval %S) nounwind
+; CHECK: call void @g(i32 %{{.*}}, i64 %{{.*}})
+
+; Verify we unpack the byval array.
+; FIXME: this sould be: call void @h(i32 %{{[a-zA-Z._0-9]*}}, i32 %{{[a-zA-Z._0-9]*}})
+; CHECK: call void @h([2 x i32]* byval %A)
+  call void @h([2 x i32]* byval %A) nounwind
   ret i32 0
 }
-
-; CHECK-LABEL: define i32 @main
-; CHECK: call void @f(i32 %{{.*}}, i64 %{{.*}})
-; CHECK: call void @g(i32 %{{.*}}, i64 %{{.*}})