[PATCH] D29169: Do not apply redundant LastCallToStaticBonus

[Taewook Oh via Phabricator via llvm-commits]

twoh updated this revision to Diff 86124.
twoh added a comment.

Add comments to the test


https://reviews.llvm.org/D29169

Files:
  lib/Transforms/IPO/Inliner.cpp
  test/Transforms/Inline/last-call-bonus.ll


Index: test/Transforms/Inline/last-call-bonus.ll
===================================================================
--- /dev/null
+++ test/Transforms/Inline/last-call-bonus.ll
@@ -0,0 +1,51 @@
+; The goal of this test is checking LastCallToStaticBonus is applied correctly.
+; For the test code below, when inliner evaluates the callsite of bar->baz, it
+; checks if inlining of bar->baz prevents ininling of foo->bar, even when
+; foo->bar inlining is more beneficial than bar->baz inlining.
+; As LastCallToStaticBonus has a massive value, and both baz and bar has only
+; one caller, the cost of foo->bar inlining and bar->baz inlining should be
+; non-trivial for inliner to compute that bar->baz inlining can actaully
+; prevent foo->bar inlining. To make the cost of these callsites big enough,
+; loop unrolling pass with very high threshold is used to preprocess the test.
+
+; RUN: opt < %s -loop-unroll -inline -unroll-threshold=15000 -inline-threshold=250 -S | FileCheck %s
+; CHECK-LABEL: define internal i32 @bar()
+
+define internal i32 @baz() {
+entry:
+  br label %bb1
+
+bb1:
+  %ind = phi i32 [ 0, %entry ], [ %inc, %bb1 ]
+  call void @extern()
+  %inc = add nsw i32 %ind, 1
+  %cmp = icmp sgt i32 %inc, 510
+  br i1 %cmp, label %ret, label %bb1
+
+ret:
+  ret i32 0
+}
+
+define internal i32 @bar() {
+entry:
+  br label %bb1
+
+bb1:
+  %ind = phi i32 [ 0, %entry ], [ %inc, %bb1 ]
+  call void @extern()
+  %inc = add nsw i32 %ind, 1
+  %cmp = icmp sgt i32 %inc, 510
+  br i1 %cmp, label %ret, label %bb1
+
+ret:
+  call i32 @baz()
+  ret i32 0
+}
+
+define i32 @foo() {
+entry:
+  call i32 @bar()
+  ret i32 0
+}
+
+declare void @extern()
Index: lib/Transforms/IPO/Inliner.cpp
===================================================================
--- lib/Transforms/IPO/Inliner.cpp
+++ lib/Transforms/IPO/Inliner.cpp
@@ -326,6 +326,7 @@
   // one is set very low by getInlineCost, in anticipation that Caller will
   // be removed entirely.  We did not account for this above unless there
   // is only one caller of Caller.
+  //if (callerWillBeRemoved && !Caller->hasOneUse())
   if (callerWillBeRemoved && !Caller->use_empty())
     TotalSecondaryCost -= InlineConstants::LastCallToStaticBonus;
 


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