[llvm] r246129 - Fixed a bug that edge weights are not assigned correctly when lowering switch statement.

[Cong Hou via llvm-commits]

Author: conghou
Date: Wed Aug 26 19:37:40 2015
New Revision: 246129

URL: http://llvm.org/viewvc/llvm-project?rev=246129&view=rev
Log:
Fixed a bug that edge weights are not assigned correctly when lowering switch statement.

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


Added:
    llvm/trunk/test/CodeGen/X86/switch-edge-weight.ll
Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=246129&r1=246128&r2=246129&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Wed Aug 26 19:37:40 2015
@@ -8033,6 +8033,7 @@ void SelectionDAGBuilder::lowerWorkItem(
       // 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(
         }
 
         // 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);
 

Added: llvm/trunk/test/CodeGen/X86/switch-edge-weight.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/switch-edge-weight.ll?rev=246129&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/switch-edge-weight.ll (added)
+++ llvm/trunk/test/CodeGen/X86/switch-edge-weight.ll Wed Aug 26 19:37:40 2015
@@ -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}