llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-codegen Author: Yingwei Zheng (dtcxzyw) <details> <summary>Changes</summary> Closes https://github.com/llvm/llvm-project/issues/137833. This patch is stacked on https://github.com/llvm/llvm-project/pull/137849. --- Full diff: https://github.com/llvm/llvm-project/pull/137851.diff 4 Files Affected: - (modified) clang/lib/CodeGen/CGExpr.cpp (+3) - (modified) clang/lib/CodeGen/CGExprScalar.cpp (+2-1) - (modified) clang/test/CodeGen/catch-nullptr-and-nonzero-offset.c (+12) - (added) clang/test/CodeGen/glibc_ptr_align.c (+22) ``````````diff diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp index bba7d1e805f3f..e9e22321e2634 100644 --- a/clang/lib/CodeGen/CGExpr.cpp +++ b/clang/lib/CodeGen/CGExpr.cpp @@ -4820,6 +4820,9 @@ bool CodeGenFunction::isUnderlyingBasePointerConstantNull(const Expr *E) { const Expr *UnderlyingBaseExpr = E->IgnoreParens(); while (auto *BaseMemberExpr = dyn_cast<MemberExpr>(UnderlyingBaseExpr)) UnderlyingBaseExpr = BaseMemberExpr->getBase()->IgnoreParens(); + if (auto *Select = dyn_cast<ConditionalOperator>(UnderlyingBaseExpr)) + return isUnderlyingBasePointerConstantNull(Select->getTrueExpr()) || + isUnderlyingBasePointerConstantNull(Select->getFalseExpr()); return getContext().isSentinelNullExpr(UnderlyingBaseExpr); } diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp index 8dbbcdaef25d8..d214d2af52563 100644 --- a/clang/lib/CodeGen/CGExprScalar.cpp +++ b/clang/lib/CodeGen/CGExprScalar.cpp @@ -4238,7 +4238,8 @@ static Value *emitPointerArithmetic(CodeGenFunction &CGF, else elemTy = CGF.ConvertTypeForMem(elementType); - if (CGF.getLangOpts().PointerOverflowDefined) + if (CGF.getLangOpts().PointerOverflowDefined || + CGF.isUnderlyingBasePointerConstantNull(pointerOperand)) return CGF.Builder.CreateGEP(elemTy, pointer, index, "add.ptr"); return CGF.EmitCheckedInBoundsGEP( diff --git a/clang/test/CodeGen/catch-nullptr-and-nonzero-offset.c b/clang/test/CodeGen/catch-nullptr-and-nonzero-offset.c index 63b6db2c2adeb..c5ae3f8bcc368 100644 --- a/clang/test/CodeGen/catch-nullptr-and-nonzero-offset.c +++ b/clang/test/CodeGen/catch-nullptr-and-nonzero-offset.c @@ -431,6 +431,18 @@ char *void_ptr(void *base, unsigned long offset) { return base + offset; } +int *constant_null_add(long offset) { + // CHECK: define{{.*}} ptr @constant_null_add(i64 noundef %[[OFFSET:.*]]) + // CHECK-NEXT: [[ENTRY:.*]]: + // CHECK-NEXT: %[[OFFSET_ADDR:.*]] = alloca i64, align 8 + // CHECK-NEXT: store i64 %[[OFFSET]], ptr %[[OFFSET_ADDR]], align 8 + // CHECK-NEXT: %[[OFFSET_RELOADED:.*]] = load i64, ptr %[[OFFSET_ADDR]], align 8 + // CHECK-NEXT: %[[ADD_PTR:.*]] = getelementptr i32, ptr null, i64 %[[OFFSET_RELOADED]] + // CHECK-NEXT: ret ptr %[[ADD_PTR]] +#line 1800 + return (int *)0 + offset; +} + #ifdef __cplusplus } #endif diff --git a/clang/test/CodeGen/glibc_ptr_align.c b/clang/test/CodeGen/glibc_ptr_align.c new file mode 100644 index 0000000000000..14968a8326509 --- /dev/null +++ b/clang/test/CodeGen/glibc_ptr_align.c @@ -0,0 +1,22 @@ +// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 5 +// RUN: %clang_cc1 -triple=x86_64-unknown-unknown -O3 -o - -emit-llvm %s | FileCheck %s + +// Make sure that we do not set inbounds flag if the base pointer may be a constant null. + +// CHECK-LABEL: define dso_local noalias ptr @glibc_ptr_align( +// CHECK-SAME: ptr noundef readnone captures(none) [[BASE:%.*]], ptr noundef [[POINTER:%.*]], i64 noundef [[ALIGN_MASK:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] { +// CHECK-NEXT: [[ENTRY:.*:]] +// CHECK-NEXT: [[SUB_PTR_LHS_CAST:%.*]] = ptrtoint ptr [[POINTER]] to i64 +// CHECK-NEXT: [[ADD:%.*]] = add nsw i64 [[ALIGN_MASK]], [[SUB_PTR_LHS_CAST]] +// CHECK-NEXT: [[NOT:%.*]] = xor i64 [[ALIGN_MASK]], -1 +// CHECK-NEXT: [[AND:%.*]] = and i64 [[ADD]], [[NOT]] +// CHECK-NEXT: [[ADD_PTR:%.*]] = getelementptr i8, ptr null, i64 [[AND]] +// CHECK-NEXT: ret ptr [[ADD_PTR]] +// +char *glibc_ptr_align(char *base, char *pointer, long align_mask) { + return (sizeof(long int) < sizeof(void *) ? (base) : (char *)0) + + (((pointer) - + (sizeof(long int) < sizeof(void *) ? (base) : (char *)0) + + (align_mask)) & + ~(align_mask)); +} `````````` </details> https://github.com/llvm/llvm-project/pull/137851 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
