[pkg-d-commits] [ldc] 42/211: PGO: remove unnecessary instrumentationn BBs for switch statements in instrumentation-disabled functions.

[Matthias Klumpp]

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mak pushed a commit to annotated tag v1.1.0
in repository ldc.

commit 8d84cc7f8cec7777659efc3baba51078c0d5405f
Author: Johan Engelen <jbc.engelen at gmail.com>
Date:   Tue Sep 27 12:18:10 2016 +0200

    PGO: remove unnecessary instrumentationn BBs for switch statements in instrumentation-disabled functions.
---
 gen/pgo.h                  |  4 +++
 gen/statements.cpp         | 14 ++++----
 tests/PGO/switch_disable.d | 79 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 90 insertions(+), 7 deletions(-)

diff --git a/gen/pgo.h b/gen/pgo.h
index 0f0906c..2f5b0ea 100644
--- a/gen/pgo.h
+++ b/gen/pgo.h
@@ -42,6 +42,7 @@ class ForeachRangeStatement;
 class CodeGenPGO {
 public:
   CodeGenPGO() {}
+  bool emitsInstrumentation() const { return false; }
   bool haveRegionCounts() const { return false; }
   uint64_t getCurrentRegionCount() const { return 0; }
   void setCurrentRegionCount(uint64_t) {}
@@ -102,6 +103,9 @@ public:
   {
   }
 
+  /// Whether or not we emit PGO instrumentation for the current function.
+  bool emitsInstrumentation() const { return emitInstrumentation; }
+
   /// Whether or not we have PGO region data for the current function. This is
   /// false both when we have no data at all and when our data has been
   /// discarded.
diff --git a/gen/statements.cpp b/gen/statements.cpp
index 75031ea..4595f49 100644
--- a/gen/statements.cpp
+++ b/gen/statements.cpp
@@ -955,7 +955,7 @@ public:
       // statement bodies, because the counters should only count the jumps
       // directly from the switch statement and not "goto default", etc.
       llvm::SwitchInst *si;
-      if (!global.params.genInstrProf) {
+      if (!PGO.emitsInstrumentation()) {
         si = llvm::SwitchInst::Create(condVal, defaultTargetBB, caseCount,
                                       irs->scopebb());
         for (size_t i = 0; i < caseCount; ++i) {
@@ -982,11 +982,11 @@ public:
           const auto cs = (*cases)[i];
           const auto body = funcGen.switchTargets.get(cs);
 
-          auto incrCaseCounter = irs->insertBBBefore(body, "incrCaseCounter");
-          irs->scope() = IRScope(incrCaseCounter);
+          auto casecntr = irs->insertBBBefore(body, "casecntr");
+          irs->scope() = IRScope(casecntr);
           PGO.emitCounterIncrement(cs);
-          llvm::BranchInst::Create(body, incrCaseCounter);
-          si->addCase(isaConstantInt(indices[i]), incrCaseCounter);
+          llvm::BranchInst::Create(body, casecntr);
+          si->addCase(isaConstantInt(indices[i]), casecntr);
         }
       }
 
@@ -1014,7 +1014,7 @@ public:
       llvm::BasicBlock *nextbb = irs->insertBBBefore(endbb, "checkcase");
       llvm::BranchInst::Create(nextbb, irs->scopebb());
 
-      if (global.params.genInstrProf) {
+      if (PGO.emitsInstrumentation()) {
         // Prepend extra BB to "default:" to increment profiling counter.
         llvm::BasicBlock *defaultcntr =
             irs->insertBBBefore(defaultTargetBB, "defaultcntr");
@@ -1034,7 +1034,7 @@ public:
         // Add case counters for PGO in front of case body
         const auto cs = (*cases)[i];
         auto casejumptargetbb = funcGen.switchTargets.get(cs);
-        if (global.params.genInstrProf) {
+        if (PGO.emitsInstrumentation()) {
           llvm::BasicBlock *casecntr =
               irs->insertBBBefore(casejumptargetbb, "casecntr");
           auto savedbb = irs->scope();
diff --git a/tests/PGO/switch_disable.d b/tests/PGO/switch_disable.d
new file mode 100644
index 0000000..a80f285
--- /dev/null
+++ b/tests/PGO/switch_disable.d
@@ -0,0 +1,79 @@
+// Test function-level enabling/disabling of instrumentation of switch statements.
+
+// RUN: %ldc -boundscheck=off -c -output-ll -fprofile-instr-generate -of=%t.ll %s && FileCheck %s --check-prefix=PROFGEN < %t.ll
+
+extern (C): // simplify name mangling for simpler string matching
+
+// PROFGEN-LABEL: @enabled(
+int enabled(int i)
+{
+    pragma(LDC_profile_instr, true);
+
+    switch (i)
+    {
+        // PROFGEN: casecntr
+    case 1:
+        return 1;
+        // PROFGEN: casecntr
+    case 2:
+        return 2;
+        // PROFGEN: defaultcntr
+    default:
+        return 3;
+    }
+}
+
+// PROFGEN-LABEL: @disabled(
+// PROFGEN-NOT: casecntr
+// PROFGEN-NOT: defaultcntr
+int disabled(int i)
+{
+    pragma(LDC_profile_instr, false);
+
+    switch (i)
+    {
+    case 1:
+        return 1;
+    case 2:
+        return 2;
+    default:
+        return 3;
+    }
+}
+
+// PROFGEN-LABEL: @bunch_of_branches_enabled(
+int bunch_of_branches_enabled(int i, int two)
+{
+    pragma(LDC_profile_instr, true);
+
+    switch (i)
+    {
+// PROFGEN: casecntr
+    case 1:
+        return 1;
+// PROFGEN: casecntr
+    case two:
+        return 2;
+// PROFGEN: defaultcntr
+    default:
+        return 3;
+    }
+}
+
+// PROFGEN-LABEL: @bunch_of_branches_disabled(
+// PROFGEN-NOT: casecntr
+// PROFGEN-NOT: defaultcntr
+int bunch_of_branches_disabled(int i, int two)
+{
+    pragma(LDC_profile_instr, false);
+
+    switch (i)
+    {
+    case 1:
+        return 1;
+    case two:
+        return 2;
+    default:
+        return 3;
+    }
+}

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