Avoid undefined divide-by-0 (#4821)
The Reciprocal function expects a divide-by-0 to return nan,and then Reciprocal will return 0.
Since the divide-by-0 is actually undefined, we will identify this case early, and return 0.
No new tests are needed because we already tests folding divide-by-0.
Fixes #4715
diff --git a/source/opt/folding_rules.cpp b/source/opt/folding_rules.cpp
index 0d8f7c8..2d778b9 100644
--- a/source/opt/folding_rules.cpp
+++ b/source/opt/folding_rules.cpp
@@ -277,6 +277,11 @@
uint32_t width = c->type()->AsFloat()->width();
assert(width == 32 || width == 64);
std::vector<uint32_t> words;
+
+ if (c->IsZero()) {
+ return 0;
+ }
+
if (width == 64) {
spvtools::utils::FloatProxy<double> result(1.0 / c->GetDouble());
if (!IsValidResult(result.getAsFloat())) return 0;
