I'm not Richard, but I agree with merging it into 3.9 nonetheless. :-) ~Aaron
On Tue, Aug 16, 2016 at 12:30 PM, Hans Wennborg via cfe-commits <cfe-commits@lists.llvm.org> wrote: > Seems reasonable to me if Richard agrees. > > On Tue, Aug 16, 2016 at 3:01 AM, James Molloy <ja...@jamesmolloy.co.uk> wrote: >> Hi Hans, >> >> [cc. Richard as code owner] >> >> I'd like to nominate this commit for 3.9. The actual code churn is tiny, and >> this fixes a problem noticed by and causing pain to the qemu project. >> >> Cheers, >> >> James >> >> On Tue, 16 Aug 2016 at 10:53 James Molloy via cfe-commits >> <cfe-commits@lists.llvm.org> wrote: >>> >>> Author: jamesm >>> Date: Tue Aug 16 04:45:36 2016 >>> New Revision: 278786 >>> >>> URL: http://llvm.org/viewvc/llvm-project?rev=278786&view=rev >>> Log: >>> Left shifts of negative values are defined if -fwrapv is set >>> >>> This means we shouldn't emit ubsan detection code or warn. >>> Fixes PR25552. >>> >>> Added: >>> cfe/trunk/test/CodeGen/wrapv-lshr-sanitize.c >>> cfe/trunk/test/Sema/negative-shift-wrapv.c >>> Modified: >>> cfe/trunk/lib/CodeGen/CGExprScalar.cpp >>> cfe/trunk/lib/Sema/SemaExpr.cpp >>> >>> Modified: cfe/trunk/lib/CodeGen/CGExprScalar.cpp >>> URL: >>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprScalar.cpp?rev=278786&r1=278785&r2=278786&view=diff >>> >>> ============================================================================== >>> --- cfe/trunk/lib/CodeGen/CGExprScalar.cpp (original) >>> +++ cfe/trunk/lib/CodeGen/CGExprScalar.cpp Tue Aug 16 04:45:36 2016 >>> @@ -2714,7 +2714,8 @@ Value *ScalarExprEmitter::EmitShl(const >>> RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, >>> "sh_prom"); >>> >>> bool SanitizeBase = CGF.SanOpts.has(SanitizerKind::ShiftBase) && >>> - Ops.Ty->hasSignedIntegerRepresentation(); >>> + Ops.Ty->hasSignedIntegerRepresentation() && >>> + !CGF.getLangOpts().isSignedOverflowDefined(); >>> bool SanitizeExponent = CGF.SanOpts.has(SanitizerKind::ShiftExponent); >>> // OpenCL 6.3j: shift values are effectively % word size of LHS. >>> if (CGF.getLangOpts().OpenCL) >>> >>> Modified: cfe/trunk/lib/Sema/SemaExpr.cpp >>> URL: >>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=278786&r1=278785&r2=278786&view=diff >>> >>> ============================================================================== >>> --- cfe/trunk/lib/Sema/SemaExpr.cpp (original) >>> +++ cfe/trunk/lib/Sema/SemaExpr.cpp Tue Aug 16 04:45:36 2016 >>> @@ -8670,7 +8670,7 @@ static void DiagnoseBadShiftValues(Sema& >>> >>> // If LHS does not have a signed type and non-negative value >>> // then, the behavior is undefined. Warn about it. >>> - if (Left.isNegative()) { >>> + if (Left.isNegative() && !S.getLangOpts().isSignedOverflowDefined()) { >>> S.DiagRuntimeBehavior(Loc, LHS.get(), >>> S.PDiag(diag::warn_shift_lhs_negative) >>> << LHS.get()->getSourceRange()); >>> >>> Added: cfe/trunk/test/CodeGen/wrapv-lshr-sanitize.c >>> URL: >>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/wrapv-lshr-sanitize.c?rev=278786&view=auto >>> >>> ============================================================================== >>> --- cfe/trunk/test/CodeGen/wrapv-lshr-sanitize.c (added) >>> +++ cfe/trunk/test/CodeGen/wrapv-lshr-sanitize.c Tue Aug 16 04:45:36 2016 >>> @@ -0,0 +1,12 @@ >>> +// RUN: %clang_cc1 -fsanitize=shift-base -emit-llvm %s -o - -triple >>> x86_64-linux-gnu -fwrapv | FileCheck %s >>> + >>> +// CHECK-LABEL: @lsh_overflow >>> +int lsh_overflow(int a, int b) { >>> + // CHECK-NOT: br >>> + // CHECK-NOT: call void @__ubsan_ >>> + // CHECK-NOT: call void @llvm.trap >>> + >>> + // CHECK: %[[RET:.*]] = shl i32 >>> + // CHECK-NEXT: ret i32 %[[RET]] >>> + return a << b; >>> +} >>> >>> Added: cfe/trunk/test/Sema/negative-shift-wrapv.c >>> URL: >>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/negative-shift-wrapv.c?rev=278786&view=auto >>> >>> ============================================================================== >>> --- cfe/trunk/test/Sema/negative-shift-wrapv.c (added) >>> +++ cfe/trunk/test/Sema/negative-shift-wrapv.c Tue Aug 16 04:45:36 2016 >>> @@ -0,0 +1,9 @@ >>> +// RUN: %clang_cc1 -Wall -ffreestanding -fsyntax-only -fwrapv -verify %s >>> + >>> +int test() { >>> + int i; >>> + i = -1 << 1; // no-warning >>> + return i; >>> +} >>> + >>> +// expected-no-diagnostics >>> >>> >>> _______________________________________________ >>> cfe-commits mailing list >>> cfe-commits@lists.llvm.org >>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits > _______________________________________________ > cfe-commits mailing list > cfe-commits@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
