Fix Phi simplification bug (shader-slang#3325)

expipiplus1 · web-flow · commit c71b12775c8b · 2023-11-13T09:02:08.000-08:00
Fixes shader-slang#3323
diff --git a/source/slang/slang-ir-peephole.cpp b/source/slang/slang-ir-peephole.cpp
@@ -845,8 +845,11 @@ struct PeepholeContext : InstPassBase
                 {
                     if (inst->hasUses())
                     {
-                        // Is argValue a global constant?
-                        if (isChildInstOf(inst, argValue->getParent()))
+                        // Is argValue not a local value, i.e. it's not a child
+                        // of a block, and it's 'visible' from inst because
+                        // inst is a descendent of argValue's parent
+                        if (!as<IRBlock>(argValue->getParent())
+                            && isChildInstOf(inst, argValue->getParent()))
                         {
                             inst->replaceUsesWith(argValue);
                             // Never remove param inst.

Original file line number	Diff line number	Diff line change
`@@ -845,8 +845,11 @@ struct PeepholeContext : InstPassBase`
`845`	`845`	`{`
`846`	`846`	`if (inst->hasUses())`
`847`	`847`	`{`
`848`		`- // Is argValue a global constant?`
`849`		`- if (isChildInstOf(inst, argValue->getParent()))`
	`848`	`+ // Is argValue not a local value, i.e. it's not a child`
	`849`	`+ // of a block, and it's 'visible' from inst because`
	`850`	`+ // inst is a descendent of argValue's parent`
	`851`	`+ if (!as<IRBlock>(argValue->getParent())`
	`852`	`+ && isChildInstOf(inst, argValue->getParent()))`
`850`	`853`	`{`
`851`	`854`	`inst->replaceUsesWith(argValue);`
`852`	`855`	`// Never remove param inst.`