[ARM][MVE] Fix location of optimized gather addresses
Fix for the address optimization for gathers and scatters which would in
some complex cases push out instructions not to the vector loop preheader,
but to other locations as well which lead to a scrambled order and the
compilation failing.
This patch ensures that said instructions are always pushed to the end
of the vector loop preheader.
Differential Revision: https://reviews.llvm.org/D78293
diff --git a/llvm/lib/Target/ARM/MVEGatherScatterLowering.cpp b/llvm/lib/Target/ARM/MVEGatherScatterLowering.cpp
index 09c6cca..e4f6d12 100644
--- a/llvm/lib/Target/ARM/MVEGatherScatterLowering.cpp
+++ b/llvm/lib/Target/ARM/MVEGatherScatterLowering.cpp
@@ -463,11 +463,7 @@
Value *OffsSecondOperand,
unsigned StartIndex) {
LLVM_DEBUG(dbgs() << "masked gathers/scatters: optimising add instruction\n");
- Instruction *InsertionPoint;
- if (isa<Instruction>(OffsSecondOperand))
- InsertionPoint = &cast<Instruction>(OffsSecondOperand)->getParent()->back();
- else
- InsertionPoint =
+ Instruction *InsertionPoint =
&cast<Instruction>(Phi->getIncomingBlock(StartIndex)->back());
// Initialize the phi with a vector that contains a sum of the constants
Instruction *NewIndex = BinaryOperator::Create(
@@ -492,11 +488,7 @@
// Create a new scalar add outside of the loop and transform it to a splat
// by which loop variable can be incremented
- Instruction *InsertionPoint;
- if (isa<Instruction>(OffsSecondOperand))
- InsertionPoint = &cast<Instruction>(OffsSecondOperand)->getParent()->back();
- else
- InsertionPoint = &cast<Instruction>(
+ Instruction *InsertionPoint = &cast<Instruction>(
Phi->getIncomingBlock(LoopIncrement == 1 ? 0 : 1)->back());
// Create a new index