Fixed a bug that edge weights are not assigned correctly when lowering switch statement.
authorCong Hou <congh@google.com>
Thu, 27 Aug 2015 00:37:40 +0000 (00:37 +0000)
committerCong Hou <congh@google.com>
Thu, 27 Aug 2015 00:37:40 +0000 (00:37 +0000)
This is a one-line-change patch that moves the update to UnhandledWeights to the correct position: it should be updated for all clusters instead of just range clusters.

Differential Revision: http://reviews.llvm.org/D12391

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246129 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
test/CodeGen/X86/switch-edge-weight.ll [new file with mode: 0644]

index 9ccd626..48811bd 100644 (file)
@@ -8033,6 +8033,7 @@ void SelectionDAGBuilder::lowerWorkItem(SwitchWorkListItem W, Value *Cond,
       // Put Cond in a virtual register to make it available from the new blocks.
       ExportFromCurrentBlock(Cond);
     }
+    UnhandledWeights -= I->Weight;
 
     switch (I->Kind) {
       case CC_JumpTable: {
@@ -8103,7 +8104,6 @@ void SelectionDAGBuilder::lowerWorkItem(SwitchWorkListItem W, Value *Cond,
         }
 
         // The false weight is the sum of all unhandled cases.
-        UnhandledWeights -= I->Weight;
         CaseBlock CB(CC, LHS, RHS, MHS, I->MBB, Fallthrough, CurMBB, I->Weight,
                      UnhandledWeights);
 
diff --git a/test/CodeGen/X86/switch-edge-weight.ll b/test/CodeGen/X86/switch-edge-weight.ll
new file mode 100644 (file)
index 0000000..c4cba43
--- /dev/null
@@ -0,0 +1,41 @@
+; RUN: llc -march=x86-64 -print-machineinstrs=expand-isel-pseudos %s -o /dev/null 2>&1 | FileCheck %s
+
+
+; CHECK-LABEL: test
+
+define void @test(i32 %x) nounwind {
+entry:
+  switch i32 %x, label %sw.default [
+    i32 54, label %sw.bb
+    i32 55, label %sw.bb
+    i32 56, label %sw.bb
+    i32 58, label %sw.bb
+    i32 67, label %sw.bb
+    i32 68, label %sw.bb
+    i32 134, label %sw.bb
+    i32 140, label %sw.bb
+  ], !prof !1
+
+sw.bb:
+  call void @foo(i32 0)
+  br label %sw.epilog
+
+sw.default:
+  call void @foo(i32 1)
+  br label %sw.epilog
+
+sw.epilog:
+  ret void
+
+; Check if weights are correctly assigned to edges generated from switch
+; statement.
+;
+; CHECK: BB#4:
+; CHECK: Successors according to CFG: BB#1(10) BB#6(10)
+; CHECK: BB#6:
+; CHECK: Successors according to CFG: BB#1(10) BB#2(10)
+}
+
+declare void @foo(i32)
+
+!1 = !{!"branch_weights", i32 10, i32 10, i32 10, i32 10, i32 10, i32 10, i32 10, i32 10, i32 10}