Handle cases where instructions can be inserted in masking blocks

Penguinwizzard · Penguinwizzard · commit ead3cade4380 · 2018-05-16T11:27:41.000-07:00
diff --git a/lib/Backend/BackwardPass.cpp b/lib/Backend/BackwardPass.cpp
@@ -3244,7 +3244,7 @@ BackwardPass::ProcessBlock(BasicBlock * block)
                     FOREACH_SLIST_ENTRY(IR::ByteCodeUsesInstr*, bcuInstr, loop->outwardSpeculationMaskInstrs)
                     {
                         // Get the upwardExposed information for the previous block
-                        IR::LabelInstr *blockLabel = bcuInstr->m_prev->AsLabelInstr();
+                        IR::LabelInstr *blockLabel = bcuInstr->GetBlockStartInstr()->AsLabelInstr();
                         BasicBlock* maskingBlock = blockLabel->GetBasicBlock();
                         // Since it's possible we have a multi-level loop structure (each with its own mask
                         // instructions and dereferenced symbol list), we may be able to avoid masking some

Original file line number	Diff line number	Diff line change
`@@ -3244,7 +3244,7 @@ BackwardPass::ProcessBlock(BasicBlock * block)`
`3244`	`3244`	`FOREACH_SLIST_ENTRY(IR::ByteCodeUsesInstr*, bcuInstr, loop->outwardSpeculationMaskInstrs)`
`3245`	`3245`	`{`
`3246`	`3246`	`// Get the upwardExposed information for the previous block`
`3247`		`- IR::LabelInstr *blockLabel = bcuInstr->m_prev->AsLabelInstr();`
	`3247`	`+ IR::LabelInstr *blockLabel = bcuInstr->GetBlockStartInstr()->AsLabelInstr();`
`3248`	`3248`	`BasicBlock* maskingBlock = blockLabel->GetBasicBlock();`
`3249`	`3249`	`// Since it's possible we have a multi-level loop structure (each with its own mask`
`3250`	`3250`	`// instructions and dereferenced symbol list), we may be able to avoid masking some`