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404f414ee1
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 llvm-svn: 336717
37 lines
971 B
C++
37 lines
971 B
C++
// RUN: %clang_cc1 -emit-llvm %s -o - | FileCheck %s
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// We expect to get a loop structure like this:
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// do.body: ; preds = %do.cond, ...
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// ...
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// br label %do.cond
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// do.cond: ; preds = %do.body
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// ...
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// br i1 %cmp, label %do.body, label %do.end
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// do.end: ; preds = %do.cond
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// ...
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//
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// Verify that the loop metadata only is put on the backedge.
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//
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// CHECK-NOT: llvm.loop
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// CHECK-LABEL: do.cond:
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// CHECK: br {{.*}}, label %do.body, label %do.end, !llvm.loop ![[LMD1:[0-9]+]]
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// CHECK-LABEL: do.end:
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// CHECK-NOT: llvm.loop
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// CHECK: ![[LMD1]] = distinct !{![[LMD1]], ![[LMD2:[0-9]+]]}
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// CHECK: ![[LMD2]] = !{!"llvm.loop.unroll.count", i32 4}
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int test(int a[], int n) {
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int i = 0;
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int sum = 0;
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#pragma unroll 4
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do
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{
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a[i] = a[i] + 1;
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sum = sum + a[i];
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i++;
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} while (i < n);
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return sum;
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}
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