6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-06-17 20:23:59 +00:00
Code Issues Projects Releases Wiki Activity

Don't eliminate a partially redundant load if it's in a landing pad.

Browse Source 
A landing pad can be jumped to only by the unwind edge of an invoke
instruction. If we eliminate a partially redundant load in a landing pad, it
will create a basic block that violates this constraint. It then leads to other
problems down the line if it tries to merge that basic block with the landing
pad. Avoid this by not eliminating the load in a landing pad.

PR17621


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193064 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling
2013-10-21 04:09:17 +00:00
parent 365f4fa6cb
commit 3e033f2923
4 changed files with 210 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
lib/Transforms/Scalar/JumpThreading.cpp
View File

@ -827,7 +827,6 @@ bool JumpThreading::ProcessBlock(BasicBlock *BB) {
return false;
}
/// SimplifyPartiallyRedundantLoad - If LI is an obviously partially redundant
/// load instruction, eliminate it by replacing it with a PHI node. This is an
/// important optimization that encourages jump threading, and needs to be run
@ -842,6 +841,12 @@ bool JumpThreading::SimplifyPartiallyRedundantLoad(LoadInst *LI) {
if (LoadBB->getSinglePredecessor())
return false;
// If the load is defined in a landing pad, it can't be partially redundant,
// because the edges between the invoke and the landing pad cannot have other
// instructions between them.
if (LoadBB->isLandingPad())
return false;
Value *LoadedPtr = LI->getOperand(0);
// If the loaded operand is defined in the LoadBB, it can't be available.