diff options
| author | Eli Friedman <eli.friedman@gmail.com> | 2012-04-16 04:30:08 +0000 |
|---|---|---|
| committer | Eli Friedman <eli.friedman@gmail.com> | 2012-04-16 04:30:08 +0000 |
| commit | 6c31cb4d8dd53ecba7c0848eda9982ecd26dfc39 (patch) | |
| tree | fa2a83c8724d8010444baaaa1b9b4f27b9881df2 | |
| parent | 82b90a380486cca52e869c2bae1f32b0eb75cb59 (diff) | |
| download | bcm5719-llvm-6c31cb4d8dd53ecba7c0848eda9982ecd26dfc39.tar.gz bcm5719-llvm-6c31cb4d8dd53ecba7c0848eda9982ecd26dfc39.zip | |
Make constant evaluation for pointer comparisons work correctly for some uncommon cases. <rdar://problem/10962435>.
llvm-svn: 154794
| -rw-r--r-- | clang/lib/AST/ExprConstant.cpp | 24 | ||||
| -rw-r--r-- | clang/test/Sema/const-eval-64.c | 7 | ||||
| -rw-r--r-- | clang/test/Sema/const-eval.c | 4 |
3 files changed, 29 insertions, 6 deletions
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 4a06e746158..4839c299765 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -5088,14 +5088,26 @@ bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { } } + // The comparison here must be unsigned, and performed with the same + // width as the pointer. + // FIXME: Knowing the base is the same for the LHS and RHS isn't enough + // for relational operators. + unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy); + uint64_t CompareLHS = LHSOffset.getQuantity(); + uint64_t CompareRHS = RHSOffset.getQuantity(); + assert(PtrSize <= 64 && "Unexpected pointer width"); + uint64_t Mask = ~0ULL >> (64 - PtrSize); + CompareLHS &= Mask; + CompareRHS &= Mask; + switch (E->getOpcode()) { default: llvm_unreachable("missing comparison operator"); - case BO_LT: return Success(LHSOffset < RHSOffset, E); - case BO_GT: return Success(LHSOffset > RHSOffset, E); - case BO_LE: return Success(LHSOffset <= RHSOffset, E); - case BO_GE: return Success(LHSOffset >= RHSOffset, E); - case BO_EQ: return Success(LHSOffset == RHSOffset, E); - case BO_NE: return Success(LHSOffset != RHSOffset, E); + case BO_LT: return Success(CompareLHS < CompareRHS, E); + case BO_GT: return Success(CompareLHS > CompareRHS, E); + case BO_LE: return Success(CompareLHS <= CompareRHS, E); + case BO_GE: return Success(CompareLHS >= CompareRHS, E); + case BO_EQ: return Success(CompareLHS == CompareRHS, E); + case BO_NE: return Success(CompareLHS != CompareRHS, E); } } } diff --git a/clang/test/Sema/const-eval-64.c b/clang/test/Sema/const-eval-64.c new file mode 100644 index 00000000000..5727a93e51f --- /dev/null +++ b/clang/test/Sema/const-eval-64.c @@ -0,0 +1,7 @@ +// RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-linux %s + +#define EVAL_EXPR(testno, expr) int test##testno = sizeof(struct{char qq[expr];}); + +// <rdar://problem/10962435> +EVAL_EXPR(1, ((char*)-1LL) + 1 == 0 ? 1 : -1) +EVAL_EXPR(2, ((char*)-1LL) + 1 < (char*) -1 ? 1 : -1) diff --git a/clang/test/Sema/const-eval.c b/clang/test/Sema/const-eval.c index f1c0485bc1d..3894d73d604 100644 --- a/clang/test/Sema/const-eval.c +++ b/clang/test/Sema/const-eval.c @@ -121,3 +121,7 @@ EVAL_EXPR(43, varfloat && constfloat) // expected-error {{must have a constant s // <rdar://problem/11205586> // (Make sure we continue to reject this.) EVAL_EXPR(44, "x"[0]); // expected-error {{variable length array}} + +// <rdar://problem/10962435> +EVAL_EXPR(45, ((char*)-1) + 1 == 0 ? 1 : -1) +EVAL_EXPR(46, ((char*)-1) + 1 < (char*) -1 ? 1 : -1) |
