[PATCH] D37074: [PGO] Set edge weights for indirectbr instruction with profile counts

[Rong Xu via Phabricator via llvm-commits]

xur created this revision.

Current PGO only annotates the edge weight for branch and switch instructions with profile counts. We should also annotate the indirectbr instruction as all the information is there.
This patch enables the annotating for indirectbr instructions.


https://reviews.llvm.org/D37074

Files:
  lib/Transforms/Instrumentation/PGOInstrumentation.cpp
  test/Transforms/PGOProfile/Inputs/indirectbr.proftext
  test/Transforms/PGOProfile/indirectbr.ll


Index: test/Transforms/PGOProfile/indirectbr.ll
===================================================================
--- test/Transforms/PGOProfile/indirectbr.ll
+++ test/Transforms/PGOProfile/indirectbr.ll
@@ -0,0 +1,36 @@
+; RUN: llvm-profdata merge %S/Inputs/indirectbr.proftext -o %t.profdata
+; RUN: opt < %s -pgo-instr-use -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
+; New PM
+; RUN: opt < %s -passes=pgo-instr-use -pgo-test-profile-file=%t.profdata -S | FileCheck %s --check-prefix=USE
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at foo.table = internal unnamed_addr constant [3 x i8*] [i8* blockaddress(@foo, %return), i8* blockaddress(@foo, %label2), i8* blockaddress(@foo, %label3)], align 16
+
+define i32 @foo(i32 %i) {
+entry:
+  %cmp = icmp ult i32 %i, 3
+  br i1 %cmp, label %if.then, label %return
+
+if.then:
+  %idxprom = zext i32 %i to i64
+  %arrayidx = getelementptr inbounds [3 x i8*], [3 x i8*]* @foo.table, i64 0, i64 %idxprom
+  %0 = load i8*, i8** %arrayidx, align 8
+  indirectbr i8* %0, [label %return, label %label2, label %label3]
+; USE:  indirectbr i8* %0, [label %return, label %label2, label %label3]
+; USE-SAME: !prof ![[BW_INDBR:[0-9]+]]
+; USE: ![[BW_INDBR]] = !{!"branch_weights", i32 63, i32 20, i32 5}
+
+label2:
+  br label %return
+
+label3:
+  br label %return
+
+return:
+  %retval.0 = phi i32 [ 3, %label3 ], [ 2, %label2 ], [ 0, %entry ], [ 1, %if.then ]
+  ret i32 %retval.0
+}
+
+
Index: test/Transforms/PGOProfile/Inputs/indirectbr.proftext
===================================================================
--- test/Transforms/PGOProfile/Inputs/indirectbr.proftext
+++ test/Transforms/PGOProfile/Inputs/indirectbr.proftext
@@ -0,0 +1,13 @@
+# IR level Instrumentation Flag
+:ir
+foo
+# Func Hash:
+40197883220
+# Num Counters:
+4
+# Counter Values:
+202
+88
+20
+5
+
Index: lib/Transforms/Instrumentation/PGOInstrumentation.cpp
===================================================================
--- lib/Transforms/Instrumentation/PGOInstrumentation.cpp
+++ lib/Transforms/Instrumentation/PGOInstrumentation.cpp
@@ -1094,7 +1094,8 @@
     TerminatorInst *TI = BB.getTerminator();
     if (TI->getNumSuccessors() < 2)
       continue;
-    if (!isa<BranchInst>(TI) && !isa<SwitchInst>(TI))
+    if (!(isa<BranchInst>(TI) || isa<SwitchInst>(TI) ||
+          isa<IndirectBrInst>(TI)))
       continue;
     if (getBBInfo(&BB).CountValue == 0)
       continue;


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