[PATCH] D72382: [ArgPromotion] Extend search for SafeToUnconditionallyLoad indices to the blocks that must be executed upon entry into the function.

[Mikhail Gudim via Phabricator via llvm-commits]

mgudim added a comment.

In D72382#1824854 <https://reviews.llvm.org/D72382#1824854>, @jdoerfert wrote:

> This should fix PR887: https://bugs.llvm.org/show_bug.cgi?id=887
>  Please verify that and include the test case from there. We should mention it in the commit message and close the bug if it works.


My patch does not make any difference. It looks like 887 is related to pass ordering: the load can be hoisted up into the entry block, but hoisting only runs after argpromotion

> 
> 
>  ---
> 
> This should also fix PR42039: https://bugs.llvm.org/show_bug.cgi?id=42039
>  Please verify that and include the test case from there. We should mention it in the commit message and close the bug if it works.

With my patch argpromotion does not happen, so I'll add this to the test cases and mention it in commit message.

> In D72382#1824701 <https://reviews.llvm.org/D72382#1824701>, @mgudim wrote:
> 
>> @jdoerfert I updated the patch as you suggested. Also, I added your example as a test.
> 
> 
> I don't see the example.

It's at the very end of control-flow3.ll:
; CHECK-LABEL: define internal i32 @callee2(i32* %P) {
define internal i32 @callee2(i32* %P) {
entry:

  br label %bb1

bb1:

  %gep0 = getelementptr i32, i32* %P, i64 0
  ; CHECK: %X = load i32, i32* %gep0
  %X = load i32, i32* %gep0
  br label %bb1

bb2:

  %gep1 = getelementptr i32, i32* %P, i64 1
  ; CHECK: %Y = load i32, i32* %gep1
  %Y = load i32, i32* %gep1
  ret i32 %X

}

define i32 @caller2() {

  %A = alloca i32
  store i32 17, i32* %A
  ; CHECK: %X = call i32 @callee2(i32* %A)
  %X = call i32 @callee2(i32* %A)
  ret i32 %X

}


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