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c5e9c8b1df
Summary: Current implementation of getLoopEstimatedTripCount returns 1 iteration less than it should. The reason is that in bottom tested loop first iteration is executed before first back branch is taken. For example for loop with !{!"branch_weights", i32 1 // taken, i32 1 // exit} metadata getLoopEstimatedTripCount gives 1 while actual number of iterations is 2.
Reviewers: Ayal, fhahn
Reviewed By: Ayal
Subscribers: mgorny, hiraditya, zzheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71990
44 lines
1.2 KiB
LLVM
44 lines
1.2 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -S -loop-unroll -loop-unroll -verify-dom-info -debug-only=loop-unroll -unroll-peel-max-count=7 2>&1 | FileCheck %s
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; REQUIRES: asserts
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declare void @f1()
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declare void @f2()
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; Check that we can peel off iterations that make conditions true.
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; The second invocation of loop-unroll will do profile based peeling of
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; remained iterations.
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define void @test1(i32 %k) !prof !4 {
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; CHECK: Loop Unroll: F[test1] Loop %for.body
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; CHECK: PEELING loop %for.body with iteration count 2!
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; CHECK: PEELING loop %for.body with iteration count 5!
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; CHECK: llvm.loop.unroll.disable
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for.body.lr.ph:
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br label %for.body
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for.body:
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%i.05 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.inc ]
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%cmp1 = icmp ult i32 %i.05, 2
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br i1 %cmp1, label %if.then, label %if.else
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if.then:
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call void @f1()
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br label %for.inc
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if.else:
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call void @f2()
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br label %for.inc
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for.inc:
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%inc = add nsw i32 %i.05, 1
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%cmp = icmp slt i32 %inc, %k
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br i1 %cmp, label %for.body, label %for.end, !llvm.loop !1, !prof !2
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for.end:
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ret void
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}
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!1 = distinct !{!1}
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!2 = !{!"branch_weights", i32 6, i32 1}
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!4 = !{!"function_entry_count", i64 1}
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