[SampleFDO] Don't treat warm callsite with inline instance in the profile as cold

We found current sampleFDO had a performance issue when triaging a regression.
For a callsite with inline instance in the profile, even if hot callsite inliner
cannot inline it, it may still execute enough times and should not be treated as
cold in regular inliner later. However, currently if such callsite is not inlined
by hot callsite inliner, and the BB where the callsite locates doesn't get
samples from other instructions inside of it, the callsite will have no profile
metadata annotated. In regular inliner cost analysis, if the callsite has no
profile annotated and its caller has profile information, it will be treated as
cold.

The fix changes the isCallsiteHot check and chooses to compare
CallsiteTotalSamples with hot cutoff value computed by ProfileSummaryInfo.

Differential Revision: https://reviews.llvm.org/D45377

llvm-svn: 332058

1 files changed, 115 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SampleProfile/warm-inline-instance.ll b/llvm/test/Transforms/SampleProfile/warm-inline-instance.ll
new file mode 100644
index 00000000000..622db49b707
--- /dev/null
+++ b/llvm/test/Transforms/SampleProfile/warm-inline-instance.ll
@@ -0,0 +1,115 @@
+; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/warm-inline-instance.prof -S | FileCheck %s
+; RUN: opt < %s -passes=sample-profile -sample-profile-file=%S/Inputs/warm-inline-instance.prof -S | FileCheck %s
+
+@.str = private unnamed_addr constant [11 x i8] c"sum is %d\0A\00", align 1
+
+; Function Attrs: nounwind uwtable
+define i32 @foo(i32 %x, i32 %y) !dbg !4 {
+entry:
+  %x.addr = alloca i32, align 4
+  %y.addr = alloca i32, align 4
+  store i32 %x, i32* %x.addr, align 4
+  store i32 %y, i32* %y.addr, align 4
+  %t0 = load i32, i32* %x.addr, align 4, !dbg !11
+  %t1 = load i32, i32* %y.addr, align 4, !dbg !11
+  %add = add nsw i32 %t0, %t1, !dbg !11
+  ret i32 %add, !dbg !11
+}
+
+define i32 @goo(i32 %x, i32 %y) {
+entry:
+  %x.addr = alloca i32, align 4
+  %y.addr = alloca i32, align 4
+  store i32 %x, i32* %x.addr, align 4
+  store i32 %y, i32* %y.addr, align 4
+  %t0 = load i32, i32* %x.addr, align 4, !dbg !11
+  %t1 = load i32, i32* %y.addr, align 4, !dbg !11
+  %add = add nsw i32 %t0, %t1, !dbg !11
+  ret i32 %add, !dbg !11
+}
+
+; Function Attrs: uwtable
+define i32 @main() !dbg !7 {
+entry:
+  %retval = alloca i32, align 4
+  %s = alloca i32, align 4
+  %i = alloca i32, align 4
+  store i32 0, i32* %retval
+  store i32 0, i32* %i, align 4, !dbg !12
+  br label %while.cond, !dbg !13
+
+while.cond:                                       ; preds = %if.end, %entry
+  %t0 = load i32, i32* %i, align 4, !dbg !14
+  %inc = add nsw i32 %t0, 1, !dbg !14
+  store i32 %inc, i32* %i, align 4, !dbg !14
+  %cmp = icmp slt i32 %t0, 400000000, !dbg !14
+  br i1 %cmp, label %while.body, label %while.end, !dbg !14
+
+while.body:                                       ; preds = %while.cond
+  %t1 = load i32, i32* %i, align 4, !dbg !16
+  %cmp1 = icmp ne i32 %t1, 100, !dbg !16
+  br i1 %cmp1, label %if.then, label %if.else, !dbg !16
+
+if.then:                                          ; preds = %while.body
+  %t2 = load i32, i32* %i, align 4, !dbg !18
+  %t3 = load i32, i32* %s, align 4, !dbg !18
+; Although the ratio of total samples of @foo vs total samples of @main is
+; small, since the total samples count is larger than hot cutoff computed by
+; ProfileSummaryInfo, we will still regard the callsite of foo as hot and
+; early inlining will inline it.
+; CHECK-LABEL: @main(
+; CHECK-NOT: call i32 @foo(i32 %t2, i32 %t3)
+  %call1 = call i32 @foo(i32 %t2, i32 %t3), !dbg !18
+  store i32 %call1, i32* %s, align 4, !dbg !18
+  br label %if.end, !dbg !18
+
+if.else:                                          ; preds = %while.body
+; call @goo 's basicblock doesn't get any sample, so no profile will be annotated.
+; CHECK: call i32 @goo(i32 2, i32 3), !dbg !{{[0-9]+}}
+; CHECK-NOT: !prof
+; CHECK-SAME: {{$}}
+  %call2 = call i32 @goo(i32 2, i32 3), !dbg !26
+  store i32 %call2, i32* %s, align 4, !dbg !20
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  br label %while.cond, !dbg !22
+
+while.end:                                        ; preds = %while.cond
+  %t4 = load i32, i32* %s, align 4, !dbg !24
+  %call3 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str, i32 0, i32 0), i32 %t4), !dbg !24
+  ret i32 0, !dbg !25
+}
+
+declare i32 @printf(i8*, ...) #2
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!8, !9}
+!llvm.ident = !{!10}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.5 ", isOptimized: false, emissionKind: NoDebug, file: !1, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
+!1 = !DIFile(filename: "calls.cc", directory: ".")
+!2 = !{}
+!4 = distinct !DISubprogram(name: "foo", line: 3, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 3, file: !1, scope: !5, type: !6, retainedNodes: !2)
+!5 = !DIFile(filename: "calls.cc", directory: ".")
+!6 = !DISubroutineType(types: !2)
+!7 = distinct !DISubprogram(name: "main", line: 7, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 7, file: !1, scope: !5, type: !6, retainedNodes: !2)
+!8 = !{i32 2, !"Dwarf Version", i32 4}
+!9 = !{i32 1, !"Debug Info Version", i32 3}
+!10 = !{!"clang version 3.5 "}
+!11 = !DILocation(line: 4, scope: !4)
+!12 = !DILocation(line: 8, scope: !7)
+!13 = !DILocation(line: 9, scope: !7)
+!14 = !DILocation(line: 9, scope: !15)
+!15 = !DILexicalBlockFile(discriminator: 2, file: !1, scope: !7)
+!16 = !DILocation(line: 10, scope: !17)
+!17 = distinct !DILexicalBlock(line: 10, column: 0, file: !1, scope: !7)
+!18 = !DILocation(line: 10, scope: !19)
+!19 = !DILexicalBlockFile(discriminator: 2, file: !1, scope: !17)
+!20 = !DILocation(line: 10, scope: !21)
+!21 = !DILexicalBlockFile(discriminator: 4, file: !1, scope: !17)
+!22 = !DILocation(line: 10, scope: !23)
+!23 = !DILexicalBlockFile(discriminator: 6, file: !1, scope: !17)
+!24 = !DILocation(line: 11, scope: !7)
+!25 = !DILocation(line: 12, scope: !7)
+!26 = !DILocation(line: 11, scope: !19)