[opt-remarks] If hotness threshold is set, ignore remarks without hotness

[anemet]

Summary

These are blocks that haven't not been executed during training. For large
projects this could make a significant difference. For the project, I was
looking at, I got an order of magnitude decrease in the size of the total YAML
files with this and r319235.

[davide]

lgtm

[anemet]

Thanks, @davide!

llvm/trunk/lib/Analysis/OptimizationRemarkEmitter.cpp

void OptimizationRemarkEmitter::computeHotness(
   if (V)
     OptDiag.setHotness(computeHotness(V));
 }
 
 void OptimizationRemarkEmitter::emit(
     DiagnosticInfoOptimizationBase &OptDiagBase) {
   auto &OptDiag = cast<DiagnosticInfoIROptimization>(OptDiagBase);
   computeHotness(OptDiag);
-  // If a diagnostic has a hotness value, then only emit it if its hotness
-  // meets the threshold.
-  if (OptDiag.getHotness() &&
-      *OptDiag.getHotness() <
-          F->getContext().getDiagnosticsHotnessThreshold()) {
+
+  // Only emit it if its hotness meets the threshold.
+  if (OptDiag.getHotness().getValueOr(0) <
     return;
   }
 
   F->getContext().diagnose(OptDiag);
 }
 
 OptimizationRemarkEmitterWrapperPass::OptimizationRemarkEmitterWrapperPass()
     : FunctionPass(ID) {

llvm/trunk/lib/CodeGen/MachineOptimizationRemarkEmitter.cpp

 
 void MachineOptimizationRemarkEmitter::emit(
     DiagnosticInfoOptimizationBase &OptDiagCommon) {
   auto &OptDiag = cast<DiagnosticInfoMIROptimization>(OptDiagCommon);
   computeHotness(OptDiag);
 
   LLVMContext &Ctx = MF.getFunction()->getContext();
 
-  // If a diagnostic has a hotness value, then only emit it if its hotness
-  // meets the threshold.
-  if (OptDiag.getHotness() &&
-      *OptDiag.getHotness() < Ctx.getDiagnosticsHotnessThreshold()) {
+  // Only emit it if its hotness meets the threshold.
+  if (OptDiag.getHotness().getValueOr(0) <
+      Ctx.getDiagnosticsHotnessThreshold()) {
     return;
   }
 
   Ctx.diagnose(OptDiag);
 }
 
 MachineOptimizationRemarkEmitterPass::MachineOptimizationRemarkEmitterPass()
     : MachineFunctionPass(ID) {

llvm/trunk/test/CodeGen/AArch64/arm64-spill-remarks-treshold-hotness.ll

+; RUN: llc < %s -mtriple=arm64-apple-ios7.0 -aarch64-neon-syntax=apple -pass-remarks-missed=regalloc \
+; RUN:       -pass-remarks-with-hotness 2>&1 | FileCheck %s
+
+; RUN: llc < %s -mtriple=arm64-apple-ios7.0 -aarch64-neon-syntax=apple -pass-remarks-missed=regalloc \
+; RUN:       -pass-remarks-with-hotness -pass-remarks-hotness-threshold=1 \
+; RUN:       2>&1 | FileCheck -check-prefix=THRESHOLD %s
+
+; CHECK: remark: /tmp/kk.c:3:20: 1 spills 1 reloads generated in loop{{$}}
+; THRESHOLD-NOT: remark
+
+define void @fpr128(<4 x float>* %p) nounwind ssp {
+entry:
+  br label %loop, !dbg !8
+
+loop:
+  %i = phi i32 [ 0, %entry], [ %i.2, %end2 ]
+  br label %loop2, !dbg !9
+
+loop2:
+  %j = phi i32 [ 0, %loop], [ %j.2, %loop2 ]
+  call void asm sideeffect "; inlineasm", "~{q0},~{q1},~{q2},~{q3},~{q4},~{q5},~{q6},~{q7},~{q8},~{q9},~{q10},~{q11},~{q12},~{q13},~{q14},~{q15},~{q16},~{q17},~{q18},~{q19},~{q20},~{q21},~{q22},~{q23},~{q24},~{q25},~{q26},~{q27},~{q28},~{q29},~{q30},~{q31},~{x0},~{x1},~{x2},~{x3},~{x4},~{x5},~{x6},~{x7},~{x8},~{x9},~{x10},~{x11},~{x12},~{x13},~{x14},~{x15},~{x16},~{x17},~{x18},~{x19},~{x20},~{x21},~{x22},~{x23},~{x24},~{x25},~{x26},~{x27},~{x28},~{fp},~{lr},~{sp},~{memory}"() nounwind
+  %j.2 = add i32 %j, 1
+  %c2 = icmp slt i32 %j.2, 100
+  br i1 %c2, label %loop2, label %end2
+
+end2:
+  call void asm sideeffect "; inlineasm", "~{q0},~{q1},~{q2},~{q3},~{q4},~{q5},~{q6},~{q7},~{q8},~{q9},~{q10},~{q11},~{q12},~{q13},~{q14},~{q15},~{q16},~{q17},~{q18},~{q19},~{q20},~{q21},~{q22},~{q23},~{q24},~{q25},~{q26},~{q27},~{q28},~{q29},~{q30},~{q31},~{x0},~{x1},~{x2},~{x3},~{x4},~{x5},~{x6},~{x7},~{x8},~{x9},~{x10},~{x11},~{x12},~{x13},~{x14},~{x15},~{x16},~{x17},~{x18},~{x19},~{x20},~{x21},~{x22},~{x23},~{x24},~{x25},~{x26},~{x27},~{x28},~{fp},~{lr},~{sp},~{memory}"() nounwind
+  %i.2 = add i32 %i, 1
+  %c = icmp slt i32 %i.2, 100
+  br i1 %c, label %loop, label %end
+
+end:
+  br label %loop3
+
+loop3:
+  %k = phi i32 [ 0, %end], [ %k.2, %loop3 ]
+  call void asm sideeffect "; inlineasm", "~{q0},~{q1},~{q2},~{q3},~{q4},~{q5},~{q6},~{q7},~{q8},~{q9},~{q10},~{q11},~{q12},~{q13},~{q14},~{q15},~{q16},~{q17},~{q18},~{q19},~{q20},~{q21},~{q22},~{q23},~{q24},~{q25},~{q26},~{q27},~{q28},~{q29},~{q30},~{q31},~{x0},~{x1},~{x2},~{x3},~{x4},~{x5},~{x6},~{x7},~{x8},~{x9},~{x10},~{x11},~{x12},~{x13},~{x14},~{x15},~{x16},~{x17},~{x18},~{x19},~{x20},~{x21},~{x22},~{x23},~{x24},~{x25},~{x26},~{x27},~{x28},~{fp},~{lr},~{sp},~{memory}"() nounwind
+  %k.2 = add i32 %k, 1
+  %c3 = icmp slt i32 %k.2, 100
+  br i1 %c3, label %loop3, label %end3, !dbg !10
+
+end3:
+  ret void
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+!llvm.ident = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: NoDebug, enums: !2)
+!1 = !DIFile(filename: "/tmp/kk.c", directory: "/tmp")
+!2 = !{}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{i32 1, !"PIC Level", i32 2}
+!5 = !{!"clang version 3.9.0 "}
+!6 = distinct !DISubprogram(name: "success", scope: !1, file: !1, line: 1, type: !7, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
+!7 = !DISubroutineType(types: !2)
+!8 = !DILocation(line: 1, column: 20, scope: !6)
+!9 = !DILocation(line: 2, column: 20, scope: !6)
+!10 = !DILocation(line: 3, column: 20, scope: !6)

llvm/trunk/test/Transforms/Inline/optimization-remarks-hotness-threshold.ll

+; RUN: opt < %s -S -inline -pass-remarks=inline \
+; RUN:    -pass-remarks-with-hotness 2>&1 | FileCheck %s
+
+; RUN: opt < %s -S -passes=inline -pass-remarks-output=%t -pass-remarks=inline \
+; RUN:    -pass-remarks-with-hotness -pass-remarks-hotness-threshold=1 2>&1 | \
+; RUN:    FileCheck -allow-empty -check-prefix=THRESHOLD %s
+
+; Check that when any threshold is specified we ignore remarks with no
+; hotness -- these are blocks that have not been executed during training.
+
+;  1     int foo() { return 1; }
+;  2
+;  3     int bar() {
+;  4       return foo();
+;  5     }
+
+; CHECK: remark: /tmp/s.c:4:10: foo inlined into bar with cost={{[0-9\-]+}} (threshold={{[0-9]+}})
+; THRESHOLD-NOT: remark
+
+; ModuleID = '/tmp/s.c'
+source_filename = "/tmp/s.c"
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+; Function Attrs: nounwind ssp uwtable
+define i32 @foo() #0 !dbg !7 {
+entry:
+  ret i32 1, !dbg !9
+}
+
+; Function Attrs: nounwind ssp uwtable
+define i32 @bar() #0 !dbg !10 {
+entry:
+  %call = call i32 @foo(), !dbg !11
+  ret i32 %call, !dbg !12
+}
+
+attributes #0 = { nounwind ssp uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="core2" "target-features"="+cx16,+fxsr,+mmx,+sse,+sse2,+sse3,+ssse3,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 4.0.0 (trunk 282540) (llvm/trunk 282542)", isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2)
+!1 = !DIFile(filename: "/tmp/s.c", directory: "/tmp")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"PIC Level", i32 2}
+!6 = !{!"clang version 4.0.0 (trunk 282540) (llvm/trunk 282542)"}
+!7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !0, variables: !2)
+!8 = !DISubroutineType(types: !2)
+!9 = !DILocation(line: 1, column: 13, scope: !7)
+!10 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 3, type: !8, isLocal: false, isDefinition: true, scopeLine: 3, isOptimized: true, unit: !0, variables: !2)
+!11 = !DILocation(line: 4, column: 10, scope: !10)
+!12 = !DILocation(line: 4, column: 3, scope: !10)