[spirv-reader][ir] Make AddOperandToTerminator smarter.
The only case where we need to fill in the terminator operand later is
if an `OpPhi` refers to a value after the phi. This means, we can just
add any constant value, or any known value to the terminator
immediately.
Bug: 429625248
Change-Id: I1d25fb70c4cfe03799a7e71517fac20b226d23f8
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/251635
Commit-Queue: dan sinclair <dsinclair@chromium.org>
Reviewed-by: James Price <jrprice@google.com>
diff --git a/src/tint/lang/spirv/reader/parser/parser.cc b/src/tint/lang/spirv/reader/parser/parser.cc
index 2436fe4..e1d253c 100644
--- a/src/tint/lang/spirv/reader/parser/parser.cc
+++ b/src/tint/lang/spirv/reader/parser/parser.cc
@@ -1201,6 +1201,10 @@
return src;
}
+ // Returns true if the value is a constant value
+ bool IdIsConstant(uint32_t id) { return SpvConstant(id) || spec_composites_.contains(id); }
+
+ // Returns true if this value is currently in scope
bool IdIsInScope(uint32_t id) {
for (auto iter = id_stack_.rbegin(); iter != id_stack_.rend(); ++iter) {
if (iter->count(id) > 0) {
@@ -2208,10 +2212,22 @@
EmitPhiInLoopContinue(inst);
}
- // Push a placeholder for the operand value. We store away the terminator/index pair along with
- // the required value and then fill it in at the end of the block emission. This is because a
- // PHI can refer to a value which is defined after the PHI itself.
void AddOperandToTerminator(core::ir::Terminator* term, uint32_t id) {
+ // If the ID is a constant, then we just directly emit it, it isn't an OpPhi value
+ if (IdIsConstant(id)) {
+ term->PushOperand(Value(id));
+ return;
+ }
+ // If we've already seen the value, and it's still in scope, then we can just emit as it
+ // isn't referencing a later value.
+ if (values_.Contains(id) && IdIsInScope(id)) {
+ term->PushOperand(Value(id));
+ return;
+ }
+
+ // Value isn't known, or isn't in scope, push a placeholder for the operand value. We store
+ // away the terminator/index pair along with the required value and then fill it in at the
+ // end of the block emission.
auto operand_idx = term->PushOperand(nullptr);
values_to_replace_.back().push_back(ReplacementValue{
.terminator = term,
