[clang][Sema] Create ConstantExprs in AnalyzeComparison #151464
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@llvm/pr-subscribers-clang Author: Timm Baeder (tbaederr) ChangesIf the This shows small speedups: https://llvm-compile-time-tracker.com/compare.php?from=cc8c941e17558ba427de06e72c8ad96d7b17ced1&to=112af8e62e734938547d50eeb7b416c8dd666f45&stat=instructions:u Full diff: https://github.com/llvm/llvm-project/pull/151464.diff 1 Files Affected:
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index c74b67106ad74..9b2eed3f5270f 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -11374,11 +11374,27 @@ static void AnalyzeComparison(Sema &S, BinaryOperator *E) {
LHS->getIntegerConstantExpr(S.Context);
// We don't care about expressions whose result is a constant.
- if (RHSValue && LHSValue)
+ if (RHSValue && LHSValue) {
+ auto *LHSCE = ConstantExpr::Create(S.Context, LHS, APValue(*LHSValue));
+ auto *RHSCE = ConstantExpr::Create(S.Context, RHS, APValue(*RHSValue));
+ E->setLHS(LHSCE);
+ E->setRHS(RHSCE);
return AnalyzeImpConvsInComparison(S, E);
+ }
// We only care about expressions where just one side is literal
if ((bool)RHSValue ^ (bool)LHSValue) {
+
+ if (LHSValue) {
+ auto *LHSCE = ConstantExpr::Create(S.Context, LHS, APValue(*LHSValue));
+ E->setLHS(LHSCE);
+ LHS = LHSCE;
+ } else if (RHSValue) {
+ auto *RHSCE = ConstantExpr::Create(S.Context, RHS, APValue(*RHSValue));
+ E->setRHS(RHSCE);
+ RHS = RHSCE;
+ }
+
// Is the constant on the RHS or LHS?
const bool RhsConstant = (bool)RHSValue;
Expr *Const = RhsConstant ? RHS : LHS;
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Oof, looks like I mixed up the patches locally when testing and didn't see this one's breakage. |
efriedma-quic
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efriedma-quic
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How do we decide where to insert ConstantExprs? Just wherever it feels convenient? Existing places where we construct a ConstantExpr are places where the language requires constant evaluation.
How does this interact with __builtin_is_constant_evaluated()?
3 participants
If the
getIntegerConstantExpr()calls succeed, we can as well replace theBinaryOperatorchildren withConstantExprs wrapping the previous LHS/RHS.This shows small speedups: https://llvm-compile-time-tracker.com/compare.php?from=cc8c941e17558ba427de06e72c8ad96d7b17ced1&to=112af8e62e734938547d50eeb7b416c8dd666f45&stat=instructions:u