Author: Eli Friedman Date: 2022-04-13T12:34:57-07:00 New Revision: d791de0e25e13cd8ae066e6f0fa03b384502b02e
URL: https://github.com/llvm/llvm-project/commit/d791de0e25e13cd8ae066e6f0fa03b384502b02e DIFF: https://github.com/llvm/llvm-project/commit/d791de0e25e13cd8ae066e6f0fa03b384502b02e.diff LOG: Restrict lvalue-to-rvalue conversions in CGExprConstant. We were generating wrong code for cxx20-consteval-crash.cpp: instead of loading a value of a variable, we were using its address as the initializer. Found while adding code to verify the size of constant initializers. Differential Revision: https://reviews.llvm.org/D123648 Added: Modified: clang/lib/CodeGen/CGExprConstant.cpp clang/test/CodeGenCXX/cxx20-consteval-crash.cpp Removed: ################################################################################ diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp index 6397ff5909942..92122f0df7b9a 100644 --- a/clang/lib/CodeGen/CGExprConstant.cpp +++ b/clang/lib/CodeGen/CGExprConstant.cpp @@ -1092,7 +1092,16 @@ class ConstExprEmitter : destAS, destTy); } - case CK_LValueToRValue: + case CK_LValueToRValue: { + // We don't really support doing lvalue-to-rvalue conversions here; any + // interesting conversions should be done in Evaluate(). But as a + // special case, allow compound literals to support the gcc extension + // allowing "struct x {int x;} x = (struct x) {};". + if (auto *E = dyn_cast<CompoundLiteralExpr>(subExpr->IgnoreParens())) + return Visit(E->getInitializer(), destType); + return nullptr; + } + case CK_AtomicToNonAtomic: case CK_NonAtomicToAtomic: case CK_NoOp: diff --git a/clang/test/CodeGenCXX/cxx20-consteval-crash.cpp b/clang/test/CodeGenCXX/cxx20-consteval-crash.cpp index c8ca6a56fb29a..c7f03776f56db 100644 --- a/clang/test/CodeGenCXX/cxx20-consteval-crash.cpp +++ b/clang/test/CodeGenCXX/cxx20-consteval-crash.cpp @@ -9,7 +9,7 @@ auto x2 = X(); // CHECK: @_ZN7PR507872x_E = external global i32, align 4 // CHECK-NEXT: @_ZN7PR507872x1E = constant i32* @_ZN7PR507872x_E, align 8 -// CHECK-NEXT: @_ZN7PR507872x2E = global i32* @_ZN7PR507872x_E, align 4 +// CHECK-NEXT: @_ZN7PR507872x2E = global i32 0, align 4 } namespace PR51484 { @@ -18,7 +18,7 @@ struct X { int val; }; consteval X g() { return {0}; } void f() { g(); } -// CHECK: define dso_local void @_ZN7PR514841fEv() #0 { +// CHECK: define dso_local void @_ZN7PR514841fEv() #1 { // CHECK: entry: // CHECK-NOT: call i32 @_ZN7PR514841gEv() // CHECK: ret void _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
