sepavloff created this revision. sepavloff added reviewers: rjmccall, aaron.ballman, efriedma, zahiraam. Herald added a project: All. sepavloff requested review of this revision. Herald added a project: clang.
When an expression is instantiated, TreeTransform skips ImplicitCastExpr nodes, assuming they are recreated when the instantiated expression is built. It breaks functions that use non-default floating-point options, because they are kept in these ImplicitCastExprs. In this case the recreated ImplicitCastExpr takes FP options from the current Sema state and not from AST node. To fix this issue FP options in Sema object are set when a compound statement is cloned in TreeTransform. This change fixes https://github.com/llvm/llvm-project/issues/64605 ([Regression 16 -> 17] Template instantiation ignores FENV_ACCESS being ON for both definition and instantiation). Repository: rG LLVM Github Monorepo https://reviews.llvm.org/D158158 Files: clang/lib/Sema/TreeTransform.h clang/test/SemaCXX/template-64605.cpp Index: clang/test/SemaCXX/template-64605.cpp =================================================================== --- /dev/null +++ clang/test/SemaCXX/template-64605.cpp @@ -0,0 +1,23 @@ +// RUN: %clang_cc1 -ast-dump -ast-dump-filter=b_64605 %s | FileCheck %s + +// https://github.com/llvm/llvm-project/issues/64605 + +#pragma STDC FENV_ACCESS ON +template <typename> +int b_64605() { + int x; + if ((float)0xFFFFFFFF != (float)0x100000000) { + x = 1; + } + return x; +} +int f() { return b_64605<void>(); } + +// CHECK: ImplicitCastExpr {{.*}} 'float' <IntegralToFloating> RoundingMath=1 AllowFEnvAccess=1 +// CHECK-NEXT: IntegerLiteral {{.*}} 4294967295 + +// CHECK: FunctionDecl {{.*}} b_64605 'int ()' implicit_instantiation +// CHECK-NEXT: TemplateArgument type 'void' + +// CHECK: ImplicitCastExpr {{.*}} 'float' <IntegralToFloating> RoundingMath=1 AllowFEnvAccess=1 +// CHECK-NEXT: IntegerLiteral {{.*}} 4294967295 Index: clang/lib/Sema/TreeTransform.h =================================================================== --- clang/lib/Sema/TreeTransform.h +++ clang/lib/Sema/TreeTransform.h @@ -7491,6 +7491,10 @@ TreeTransform<Derived>::TransformCompoundStmt(CompoundStmt *S, bool IsStmtExpr) { Sema::CompoundScopeRAII CompoundScope(getSema()); + Sema::FPFeaturesStateRAII FPSave(getSema()); + if (S->hasStoredFPFeatures()) + getSema().resetFPOptions( + S->getStoredFPFeatures().applyOverrides(getSema().getLangOpts())); const Stmt *ExprResult = S->getStmtExprResult(); bool SubStmtInvalid = false;
Index: clang/test/SemaCXX/template-64605.cpp =================================================================== --- /dev/null +++ clang/test/SemaCXX/template-64605.cpp @@ -0,0 +1,23 @@ +// RUN: %clang_cc1 -ast-dump -ast-dump-filter=b_64605 %s | FileCheck %s + +// https://github.com/llvm/llvm-project/issues/64605 + +#pragma STDC FENV_ACCESS ON +template <typename> +int b_64605() { + int x; + if ((float)0xFFFFFFFF != (float)0x100000000) { + x = 1; + } + return x; +} +int f() { return b_64605<void>(); } + +// CHECK: ImplicitCastExpr {{.*}} 'float' <IntegralToFloating> RoundingMath=1 AllowFEnvAccess=1 +// CHECK-NEXT: IntegerLiteral {{.*}} 4294967295 + +// CHECK: FunctionDecl {{.*}} b_64605 'int ()' implicit_instantiation +// CHECK-NEXT: TemplateArgument type 'void' + +// CHECK: ImplicitCastExpr {{.*}} 'float' <IntegralToFloating> RoundingMath=1 AllowFEnvAccess=1 +// CHECK-NEXT: IntegerLiteral {{.*}} 4294967295 Index: clang/lib/Sema/TreeTransform.h =================================================================== --- clang/lib/Sema/TreeTransform.h +++ clang/lib/Sema/TreeTransform.h @@ -7491,6 +7491,10 @@ TreeTransform<Derived>::TransformCompoundStmt(CompoundStmt *S, bool IsStmtExpr) { Sema::CompoundScopeRAII CompoundScope(getSema()); + Sema::FPFeaturesStateRAII FPSave(getSema()); + if (S->hasStoredFPFeatures()) + getSema().resetFPOptions( + S->getStoredFPFeatures().applyOverrides(getSema().getLangOpts())); const Stmt *ExprResult = S->getStmtExprResult(); bool SubStmtInvalid = false;
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