[PATCH] D33746: [PGO] Dump branch condition type, branch probability and branch hotness as optimization remarks

[David Li via Phabricator via llvm-commits]

davidxl created this revision.

This feature is intended to be used to collect branch probability statistics and the statistics can be used to guided the tuning of static branch prediction (which has not been fully tuned).

Sample output from perlbmk:

: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 1) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 1) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 1061250) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 11633) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 13537184) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 146) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 1460) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 152) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 154393) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 154627) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 177) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 2) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 2) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 22) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 247756) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 3) [-Rpass-analysis=pgo-use-annot]
: eq_i32_Const is true with probability : 0x00000000 / 0x80000000 = 0.00% (total count : 3) [-Rpass-analysis=pgo-use-a


https://reviews.llvm.org/D33746

Files:
  lib/Transforms/Instrumentation/PGOInstrumentation.cpp
  test/Transforms/PGOProfile/branch1.ll

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