Author: OverMighty Date: 2024-03-29T14:01:19-07:00 New Revision: cf73f136c5e22e7e4090fc762456ace47752a898
URL: https://github.com/llvm/llvm-project/commit/cf73f136c5e22e7e4090fc762456ace47752a898 DIFF: https://github.com/llvm/llvm-project/commit/cf73f136c5e22e7e4090fc762456ace47752a898.diff LOG: [clang][ExprConst] Fix second arg of __builtin_{clzg,ctzg} not always being evaluated (#86742) Even if we don't actually use the value of the second argument, we have to evaluate it for side-effects. --------- Co-authored-by: Richard Smith <rich...@metafoo.co.uk> Added: clang/test/Sema/constant-builtins-all-args-evaluated.cpp Modified: clang/lib/AST/ExprConstant.cpp Removed: ################################################################################ diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 5a36621dc5cce2..dae8f32fc02951 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -12361,12 +12361,17 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, if (!EvaluateInteger(E->getArg(0), Val, Info)) return false; + std::optional<APSInt> Fallback; + if (BuiltinOp == Builtin::BI__builtin_clzg && E->getNumArgs() > 1) { + APSInt FallbackTemp; + if (!EvaluateInteger(E->getArg(1), FallbackTemp, Info)) + return false; + Fallback = FallbackTemp; + } + if (!Val) { - if (BuiltinOp == Builtin::BI__builtin_clzg && E->getNumArgs() > 1) { - if (!EvaluateInteger(E->getArg(1), Val, Info)) - return false; - return Success(Val, E); - } + if (Fallback) + return Success(*Fallback, E); // When the argument is 0, the result of GCC builtins is undefined, // whereas for Microsoft intrinsics, the result is the bit-width of the @@ -12425,12 +12430,17 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, if (!EvaluateInteger(E->getArg(0), Val, Info)) return false; + std::optional<APSInt> Fallback; + if (BuiltinOp == Builtin::BI__builtin_ctzg && E->getNumArgs() > 1) { + APSInt FallbackTemp; + if (!EvaluateInteger(E->getArg(1), FallbackTemp, Info)) + return false; + Fallback = FallbackTemp; + } + if (!Val) { - if (BuiltinOp == Builtin::BI__builtin_ctzg && E->getNumArgs() > 1) { - if (!EvaluateInteger(E->getArg(1), Val, Info)) - return false; - return Success(Val, E); - } + if (Fallback) + return Success(*Fallback, E); return Error(E); } diff --git a/clang/test/Sema/constant-builtins-all-args-evaluated.cpp b/clang/test/Sema/constant-builtins-all-args-evaluated.cpp new file mode 100644 index 00000000000000..db55e24cecda7a --- /dev/null +++ b/clang/test/Sema/constant-builtins-all-args-evaluated.cpp @@ -0,0 +1,34 @@ +// RUN: %clang_cc1 -fsyntax-only -verify %s +// expected-no-diagnostics + +constexpr int test_clzg_0() { + int x = 0; + (void)__builtin_clzg(0U, ++x); + return x; +} + +static_assert(test_clzg_0() == 1); + +constexpr int test_clzg_1() { + int x = 0; + (void)__builtin_clzg(1U, ++x); + return x; +} + +static_assert(test_clzg_1() == 1); + +constexpr int test_ctzg_0() { + int x = 0; + (void)__builtin_ctzg(0U, ++x); + return x; +} + +static_assert(test_ctzg_0() == 1); + +constexpr int test_ctzg_1() { + int x = 0; + (void)__builtin_ctzg(1U, ++x); + return x; +} + +static_assert(test_ctzg_1() == 1); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
