Author: bjope Date: Tue Jul 10 12:55:02 2018 New Revision: 336717 URL: http://llvm.org/viewvc/llvm-project?rev=336717&view=rev Log: Patch to fix pragma metadata for do-while loops
Summary: Make sure that loop metadata only is put on the backedge when expanding a do-while loop. Previously we added the loop metadata also on the branch in the pre-header. That could confuse optimization passes and result in the loop metadata being associated with the wrong loop. Fixes https://bugs.llvm.org/show_bug.cgi?id=38011 Committing on behalf of deepak2427 (Deepak Panickal) Reviewers: #clang, ABataev, hfinkel, aaron.ballman, bjope Reviewed By: bjope Subscribers: bjope, rsmith, shenhan, zzheng, xbolva00, lebedev.ri, cfe-commits Tags: #clang Differential Revision: https://reviews.llvm.org/D48721 Added: cfe/trunk/test/CodeGen/pragma-do-while.cpp Modified: cfe/trunk/lib/CodeGen/CGStmt.cpp Modified: cfe/trunk/lib/CodeGen/CGStmt.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGStmt.cpp?rev=336717&r1=336716&r2=336717&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/CGStmt.cpp (original) +++ cfe/trunk/lib/CodeGen/CGStmt.cpp Tue Jul 10 12:55:02 2018 @@ -777,11 +777,6 @@ void CodeGenFunction::EmitDoStmt(const D // Emit the body of the loop. llvm::BasicBlock *LoopBody = createBasicBlock("do.body"); - const SourceRange &R = S.getSourceRange(); - LoopStack.push(LoopBody, CGM.getContext(), DoAttrs, - SourceLocToDebugLoc(R.getBegin()), - SourceLocToDebugLoc(R.getEnd())); - EmitBlockWithFallThrough(LoopBody, &S); { RunCleanupsScope BodyScope(*this); @@ -790,6 +785,11 @@ void CodeGenFunction::EmitDoStmt(const D EmitBlock(LoopCond.getBlock()); + const SourceRange &R = S.getSourceRange(); + LoopStack.push(LoopBody, CGM.getContext(), DoAttrs, + SourceLocToDebugLoc(R.getBegin()), + SourceLocToDebugLoc(R.getEnd())); + // C99 6.8.5.2: "The evaluation of the controlling expression takes place // after each execution of the loop body." Added: cfe/trunk/test/CodeGen/pragma-do-while.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/pragma-do-while.cpp?rev=336717&view=auto ============================================================================== --- cfe/trunk/test/CodeGen/pragma-do-while.cpp (added) +++ cfe/trunk/test/CodeGen/pragma-do-while.cpp Tue Jul 10 12:55:02 2018 @@ -0,0 +1,36 @@ +// RUN: %clang_cc1 -emit-llvm %s -o - | FileCheck %s + +// We expect to get a loop structure like this: +// do.body: ; preds = %do.cond, ... +// ... +// br label %do.cond +// do.cond: ; preds = %do.body +// ... +// br i1 %cmp, label %do.body, label %do.end +// do.end: ; preds = %do.cond +// ... +// +// Verify that the loop metadata only is put on the backedge. +// +// CHECK-NOT: llvm.loop +// CHECK-LABEL: do.cond: +// CHECK: br {{.*}}, label %do.body, label %do.end, !llvm.loop ![[LMD1:[0-9]+]] +// CHECK-LABEL: do.end: +// CHECK-NOT: llvm.loop +// CHECK: ![[LMD1]] = distinct !{![[LMD1]], ![[LMD2:[0-9]+]]} +// CHECK: ![[LMD2]] = !{!"llvm.loop.unroll.count", i32 4} + +int test(int a[], int n) { + int i = 0; + int sum = 0; + +#pragma unroll 4 + do + { + a[i] = a[i] + 1; + sum = sum + a[i]; + i++; + } while (i < n); + + return sum; +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
