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8e67214b2f
Summary: The PGO gen/use passes currently fail with an assert failure if there's a critical edge whose source is an IndirectBr instruction and that edge needs to be instrumented. To avoid this in certain cases, split IndirectBr critical edges in the PGO gen/use passes. This works for blocks with single indirectbr predecessors, but not for those with multiple indirectbr predecessors (splitting an IndirectBr critical edge isn't always possible.) Reviewers: davidxl, xur Reviewed By: davidxl Subscribers: efriedma, llvm-commits, mehdi_amini Differential Revision: https://reviews.llvm.org/D40699 llvm-svn: 320511
51 lines
2.3 KiB
LLVM
51 lines
2.3 KiB
LLVM
; RUN: llvm-profdata merge %S/Inputs/indirectbr.proftext -o %t.profdata
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; RUN: opt < %s -pgo-instr-use -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
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; New PM
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; RUN: opt < %s -passes=pgo-instr-use -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
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; RUN: opt < %s -passes=pgo-instr-use -pgo-test-profile-file=%t.profdata -S | opt -S -analyze -branch-prob | FileCheck %s --check-prefix=BRANCHPROB
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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@foo.table = internal unnamed_addr constant [3 x i8*] [i8* blockaddress(@foo, %return), i8* blockaddress(@foo, %label2), i8* blockaddress(@foo, %label3)], align 16
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define i32 @foo(i32 %i) {
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entry:
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%cmp = icmp ult i32 %i, 3
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br i1 %cmp, label %if.then, label %return
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if.then:
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%idxprom = zext i32 %i to i64
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%arrayidx = getelementptr inbounds [3 x i8*], [3 x i8*]* @foo.table, i64 0, i64 %idxprom
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%0 = load i8*, i8** %arrayidx, align 8
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indirectbr i8* %0, [label %return, label %label2, label %label3]
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; USE: indirectbr i8* %0, [label %return, label %label2, label %label3]
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; USE-SAME: !prof ![[BW_INDBR:[0-9]+]]
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; USE: ![[BW_INDBR]] = !{!"branch_weights", i32 63, i32 20, i32 5}
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label2:
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br label %return
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label3:
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br label %return
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return:
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%retval.0 = phi i32 [ 3, %label3 ], [ 2, %label2 ], [ 0, %entry ], [ 1, %if.then ]
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ret i32 %retval.0
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}
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; BRANCHPROB: Printing analysis 'Branch Probability Analysis' for function 'foo':
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; BRANCHPROB:---- Branch Probabilities ----
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; BRANCHPROB: edge entry -> if.then probability is 0x37c32b17 / 0x80000000 = 43.56%
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; BRANCHPROB: edge entry -> return.clone probability is 0x483cd4e9 / 0x80000000 = 56.44%
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; BRANCHPROB: edge if.then -> return probability is 0x5ba2e8ba / 0x80000000 = 71.59%
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; BRANCHPROB: edge if.then -> label2 probability is 0x1d1745d1 / 0x80000000 = 22.73%
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; BRANCHPROB: edge if.then -> label3 probability is 0x0745d174 / 0x80000000 = 5.68%
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; BRANCHPROB: edge label2 -> return.clone probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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; BRANCHPROB: edge label3 -> return.clone probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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; BRANCHPROB: edge return -> .split probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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; BRANCHPROB: edge return.clone -> .split probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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