[PATCH] D94180: [SimplifyCFG] Optimize CFG when null is passed to a function with nonnull argument.

[Dávid Bolvanský via Phabricator via llvm-commits]

xbolva00 added a comment.

  define void @test9_gep_mismatch(i1 %X, i8* %Y,  i8* %P) {
  ; CHECK-LABEL: @test9_gep_mismatch(
  ; CHECK-NEXT:  entry:
  ; CHECK-NEXT:    [[SPEC_SELECT:%.*]] = select i1 [[X:%.*]], i8* null, i8* [[Y:%.*]]
  ; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds i8, i8* [[P:%.*]], i64 0
  ; CHECK-NEXT:    [[TMP0:%.*]] = call i8* @foo(i8* [[GEP]])
  ; CHECK-NEXT:    ret void
  ;
  entry:
    br i1 %X, label %if, label %else
  
  if:
    br label %else
  
  else:
    %phi = phi i8* [ %Y, %entry ], [ null, %if ]
    %gep = getelementptr inbounds i8, i8* %phi, i64 7
    call i8* @foo(i8* %gep)
    ret void
  }

So for this case,

Use is

  call i8* @foo(i8* %gep)

I is

  %gep = getelementptr inbounds i8, i8* %phi, i64 7

and V is  a incoming value from phi. We bailt out if V is not constant, it needs to be null value.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D94180/new/

https://reviews.llvm.org/D94180