[llvm] r369283 - [CGP] Remove ModifiedDT from the makeBitReverse loop

[Craig Topper via llvm-commits]

Author: ctopper
Date: Mon Aug 19 11:02:24 2019
New Revision: 369283

URL: http://llvm.org/viewvc/llvm-project?rev=369283&view=rev
Log:
[CGP] Remove ModifiedDT from the makeBitReverse loop

I don't think anything in this loop modifies the control flow and we don't restart any iteration after setting the flag.

This code was added in http://reviews.llvm.org/D16893 but looking at the test case added there the code that caused the dominator tree to change was merging blocks with their predecessor not the bitreverse optimization.

Differential Revision: https://reviews.llvm.org/D66366

Modified:
    llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp

Modified: llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp?rev=369283&r1=369282&r2=369283&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp (original)
+++ llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp Mon Aug 19 11:02:24 2019
@@ -7104,7 +7104,6 @@ bool CodeGenPrepare::optimizeBlock(Basic
     for (auto &I : reverse(BB)) {
       if (makeBitReverse(I, *DL, *TLI)) {
         MadeBitReverse = MadeChange = true;
-        ModifiedDT = true;
         break;
       }
     }