[llvm] [AMDGPU] Restore the default rounding mode before calls and returns (PR #222247)

[Arseniy Obolenskiy via llvm-commits]

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@@ -122,6 +127,15 @@ class SIModeRegister {
 
   bool Changed = false;
 
+  // Set during Phase 1. A restore at a boundary would undo an explicit request,
+  // so the mixed case is not handled.
+  bool AnyNonDefaultMode = false;
+  bool AnyWritesRoundMode = false;
+
+  bool enforceCallBoundary() const {
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aobolensk wrote:

inlined

https://github.com/llvm/llvm-project/pull/222247