[SampleFDO] handle ProfileSampleAccurate when initializing function entry count

ProfileSampleAccurate is used to indicate the profile has exact match to the
code to be optimized.

Previously ProfileSampleAccurate is handled in ProfileSummaryInfo::isColdCallSite
and ProfileSummaryInfo::isColdBlock. A better solution is to initialize function
entry count to 0 when ProfileSampleAccurate is true, so we don't have to handle
ProfileSampleAccurate in multiple places.

Differential Revision: https://reviews.llvm.org/D55660

llvm-svn: 349088

2 files changed, 83 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SampleProfile/inline-cold-callsite-samplepgo.ll b/llvm/test/Transforms/SampleProfile/inline-cold-callsite-samplepgo.ll
new file mode 100644
index 00000000000..de2fa7cdcbf
--- /dev/null
+++ b/llvm/test/Transforms/SampleProfile/inline-cold-callsite-samplepgo.ll
@@ -0,0 +1,31 @@
+; For SamplePGO, if -profile-sample-accurate is specified, cold callsite
+; heuristics should be honored if the caller has no profile.
+
+; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/inline.prof -inline -S -inline-cold-callsite-threshold=0 | FileCheck %s
+; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/inline.prof -profile-sample-accurate -inline -S -inline-cold-callsite-threshold=0 | FileCheck %s --check-prefix ACCURATE
+
+declare void @extern()
+define void @callee() {
+  call void @extern()
+  ret void
+}
+
+define void @caller(i32 %y1) {
+; CHECK-LABEL: @caller
+; CHECK-NOT: call void @callee
+; ACCURATE-LABEL: @caller
+; ACCURATE: call void @callee
+  call void @callee()
+  ret void
+}
+
+define void @caller_accurate(i32 %y1) #0 {
+; CHECK-LABEL: @caller_accurate
+; CHECK: call void @callee
+; ACCURATE-LABEL: @caller_accurate
+; ACCURATE: call void @callee
+  call void @callee()
+  ret void
+}
+
+attributes #0 = { "profile-sample-accurate" }
diff --git a/llvm/test/Transforms/SampleProfile/section-accurate-samplepgo.ll b/llvm/test/Transforms/SampleProfile/section-accurate-samplepgo.ll
new file mode 100644
index 00000000000..3a985ff7b5e
--- /dev/null
+++ b/llvm/test/Transforms/SampleProfile/section-accurate-samplepgo.ll
@@ -0,0 +1,52 @@
+; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/inline.prof -codegenprepare -S | FileCheck %s
+; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/inline.prof -codegenprepare -profile-sample-accurate -S | FileCheck %s --check-prefix ACCURATE
+
+target triple = "x86_64-pc-linux-gnu"
+
+; The test checks that function without profile gets unlikely section prefix
+; if -profile-sample-accurate is specified or the function has the
+; profile-sample-accurate attribute.
+
+declare void @hot_func()
+
+; CHECK-NOT: foo_not_in_profile{{.*}}!section_prefix
+; CHECK: foo_not_in_profile{{.*}}!prof ![[UNKNOWN_ID:[0-9]+]]
+; ACCURATE: foo_not_in_profile{{.*}}!prof ![[ZERO_ID:[0-9]+]] !section_prefix ![[COLD_ID:[0-9]+]]
+; The function not appearing in profile is cold when -profile-sample-accurate
+; is on.
+define void @foo_not_in_profile() {
+  call void @hot_func()
+  ret void
+}
+
+; CHECK: bar_not_in_profile{{.*}}!prof ![[ZERO_ID:[0-9]+]] !section_prefix ![[COLD_ID:[0-9]+]]
+; ACCURATE: bar_not_in_profile{{.*}}!prof ![[ZERO_ID:[0-9]+]] !section_prefix ![[COLD_ID:[0-9]+]]
+; The function not appearing in profile is cold when the func has
+; profile-sample-accurate attribute.
+define void @bar_not_in_profile() #0 {
+  call void @hot_func()
+  ret void
+}
+
+attributes #0 = { "profile-sample-accurate" }
+
+; CHECK: ![[UNKNOWN_ID]] = !{!"function_entry_count", i64 -1}
+; CHECK: ![[ZERO_ID]] = !{!"function_entry_count", i64 0}
+; CHECK: ![[COLD_ID]] = !{!"function_section_prefix", !".unlikely"}
+; ACCURATE: ![[ZERO_ID]] = !{!"function_entry_count", i64 0}
+; ACCURATE: ![[COLD_ID]] = !{!"function_section_prefix", !".unlikely"}
+!llvm.module.flags = !{!1}
+!1 = !{i32 1, !"ProfileSummary", !2}
+!2 = !{!3, !4, !5, !6, !7, !8, !9, !10}
+!3 = !{!"ProfileFormat", !"SampleProfile"}
+!4 = !{!"TotalCount", i64 10000}
+!5 = !{!"MaxCount", i64 1000}
+!6 = !{!"MaxInternalCount", i64 1}
+!7 = !{!"MaxFunctionCount", i64 1000}
+!8 = !{!"NumCounts", i64 3}
+!9 = !{!"NumFunctions", i64 3}
+!10 = !{!"DetailedSummary", !11}
+!11 = !{!12, !13, !14}
+!12 = !{i32 10000, i64 100, i32 1}
+!13 = !{i32 999000, i64 100, i32 1}
+!14 = !{i32 999999, i64 1, i32 2}