[Inliner] Do not mix callsite and callee hotness based updates.

Update threshold based on callee's hotness only when BFI is not available.
Otherwise use only callsite's hotness. This makes it easier to reason about
hotness related threshold updates.

Differential revision: https://reviews.llvm.org/D33157

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303210 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/InlineCost.cpp b/lib/Analysis/InlineCost.cpp
index 44c14cb17c22ccd396da5032c64e4e21a849ac44..4702569126c6ee6240a2ee4c101173c555e02691 100644 (file)
--- a/lib/Analysis/InlineCost.cpp
+++ b/lib/Analysis/InlineCost.cpp
@@ -669,21 +669,33 @@ void CallAnalyzer::updateThreshold(CallSite CS, Function &Callee) {
       Threshold = MaxIfValid(Threshold, Params.HintThreshold);
     if (PSI) {
       BlockFrequencyInfo *CallerBFI = GetBFI ? &((*GetBFI)(*Caller)) : nullptr;
-      if (PSI->isHotCallSite(CS, CallerBFI)) {
-        DEBUG(dbgs() << "Hot callsite.\n");
-        Threshold = Params.HotCallSiteThreshold.getValue();
-      } else if (PSI->isFunctionEntryHot(&Callee)) {
-        DEBUG(dbgs() << "Hot callee.\n");
-        // If callsite hotness can not be determined, we may still know
-        // that the callee is hot and treat it as a weaker hint for threshold
-        // increase.
-        Threshold = MaxIfValid(Threshold, Params.HintThreshold);
-      } else if (PSI->isColdCallSite(CS, CallerBFI)) {
-        DEBUG(dbgs() << "Cold callsite.\n");
-        Threshold = MinIfValid(Threshold, Params.ColdCallSiteThreshold);
-      } else if (PSI->isFunctionEntryCold(&Callee)) {
-        DEBUG(dbgs() << "Cold callee.\n");
-        Threshold = MinIfValid(Threshold, Params.ColdThreshold);
+      // FIXME: After switching to the new passmanager, simplify the logic below
+      // by checking only the callsite hotness/coldness. The check for CallerBFI
+      // exists only because we do not have BFI available with the old PM.
+      //
+      // Use callee's hotness information only if we have no way of determining
+      // callsite's hotness information. Callsite hotness can be determined if
+      // sample profile is used (which adds hotness metadata to calls) or if
+      // caller's BlockFrequencyInfo is available.
+      if (CallerBFI || PSI->hasSampleProfile()) {
+        if (PSI->isHotCallSite(CS, CallerBFI)) {
+          DEBUG(dbgs() << "Hot callsite.\n");
+          Threshold = Params.HotCallSiteThreshold.getValue();
+        } else if (PSI->isColdCallSite(CS, CallerBFI)) {
+          DEBUG(dbgs() << "Cold callsite.\n");
+          Threshold = MinIfValid(Threshold, Params.ColdCallSiteThreshold);
+        }
+      } else {
+        if (PSI->isFunctionEntryHot(&Callee)) {
+          DEBUG(dbgs() << "Hot callee.\n");
+          // If callsite hotness can not be determined, we may still know
+          // that the callee is hot and treat it as a weaker hint for threshold
+          // increase.
+          Threshold = MaxIfValid(Threshold, Params.HintThreshold);
+        } else if (PSI->isFunctionEntryCold(&Callee)) {
+          DEBUG(dbgs() << "Cold callee.\n");
+          Threshold = MinIfValid(Threshold, Params.ColdThreshold);
+        }
       }
     }
   }

diff --git a/test/Transforms/Inline/inline-hot-callee.ll b/test/Transforms/Inline/inline-hot-callee.ll
index da6e52343b2d549e3f0cf37e265b60e9a046337e..dad57440063bdb13b3e71c9f65ed227eb7ce8bee 100644 (file)
--- a/test/Transforms/Inline/inline-hot-callee.ll
+++ b/test/Transforms/Inline/inline-hot-callee.ll
@@ -1,10 +1,10 @@
 ; RUN: opt < %s -inline -inline-threshold=0 -inlinehint-threshold=100 -S | FileCheck %s
-; RUN: opt < %s -passes='require<profile-summary>,cgscc(inline)' -inline-threshold=0 -inlinehint-threshold=100 -S | FileCheck %s
 
-; This tests that a hot callee gets the (higher) inlinehint-threshold even without
-; inline hints and gets inlined because the cost is less than inlinehint-threshold.
-; A cold callee with identical body does not get inlined because cost exceeds the
-; inline-threshold
+; This tests that a hot callee gets the (higher) inlinehint-threshold even
+; without inline hints and gets inlined because the cost is less than
+; inlinehint-threshold. A cold callee with identical body does not get inlined
+; because cost exceeds the inline-threshold. This test is relevant only when the
+; old pass manager is used.
 
 define i32 @callee1(i32 %x) !prof !21 {
   %x1 = add i32 %x, 1