Skip to content
Commit e802d507 authored by Juergen Ributzka's avatar Juergen Ributzka
Browse files

[Constant Hoisting] Fix multiple entries for the same basic block in PHI nodes.

A PHI node usually has only one value/basic block pair per incoming basic block.
In the case of a switch statement it is possible that a following PHI node may
have more than one such pair per incoming basic block. E.g.:
%0 = phi i64 [ 123456, %case2 ], [ 654321, %Entry ], [ 654321, %Entry ]
This is valid and the verfier doesn't complain, because both values are the
same.

Constant hoisting materializes the constant for each operand separately and the
value is still the same, but the variable names have changed. As a result the
verfier can't recognize anymore that they are the same value and complains.

This fix adds special update code for PHI node in constant hoisting to prevent
this corner case.

This fixes <rdar://problem/16394449>

llvm-svn: 204537
parent 5b0aacf1
Loading
Loading
Loading
Loading
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment