[llvm] r281339 - [Hexagon] Clear the flow queue after visiting a single instruction

[Krzysztof Parzyszek via llvm-commits]

Author: kparzysz
Date: Tue Sep 13 09:36:55 2016
New Revision: 281339

URL: http://llvm.org/viewvc/llvm-project?rev=281339&view=rev
Log:
[Hexagon] Clear the flow queue after visiting a single instruction

Added:
    llvm/trunk/test/CodeGen/Hexagon/bit-visit-flowq.ll
Modified:
    llvm/trunk/lib/Target/Hexagon/BitTracker.cpp

Modified: llvm/trunk/lib/Target/Hexagon/BitTracker.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Hexagon/BitTracker.cpp?rev=281339&r1=281338&r2=281339&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Hexagon/BitTracker.cpp (original)
+++ llvm/trunk/lib/Target/Hexagon/BitTracker.cpp Tue Sep 13 09:36:55 2016
@@ -1054,6 +1054,11 @@ void BT::visit(const MachineInstr &MI) {
   assert(!MI.isBranch() && "Only non-branches are allowed");
   InstrExec.insert(&MI);
   visitNonBranch(MI);
+  // The call to visitNonBranch could propagate the changes until a branch
+  // is actually visited. This could result in adding CFG edges to the flow
+  // queue. Since the queue won't be processed, clear it.
+  while (!FlowQ.empty())
+    FlowQ.pop();
 }
 
 

Added: llvm/trunk/test/CodeGen/Hexagon/bit-visit-flowq.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Hexagon/bit-visit-flowq.ll?rev=281339&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Hexagon/bit-visit-flowq.ll (added)
+++ llvm/trunk/test/CodeGen/Hexagon/bit-visit-flowq.ll Tue Sep 13 09:36:55 2016
@@ -0,0 +1,47 @@
+; RUN: llc -march=hexagon < %s | FileCheck %s
+; REQUIRES: asserts
+
+; Check that we don't crash.
+; CHECK: call bar
+
+target triple = "hexagon"
+
+ at debug = external hidden unnamed_addr global i1, align 4
+
+; Function Attrs: nounwind
+define void @foo() local_unnamed_addr #0 {
+entry:
+  br label %if.end5
+
+if.end5:                                          ; preds = %entry
+  br i1 undef, label %if.then12, label %if.end13
+
+if.then12:                                        ; preds = %if.end5
+  unreachable
+
+if.end13:                                         ; preds = %if.end5
+  br label %for.cond
+
+for.cond:                                         ; preds = %if.end13
+  %or.cond288 = or i1 undef, undef
+  br i1 undef, label %if.then44, label %if.end51
+
+if.then44:                                        ; preds = %for.cond
+  tail call void @bar() #0
+  br label %if.end51
+
+if.end51:                                         ; preds = %if.then44, %for.cond
+  %.b433 = load i1, i1* @debug, align 4
+  %or.cond290 = and i1 %or.cond288, %.b433
+  br i1 %or.cond290, label %if.then55, label %if.end63
+
+if.then55:                                        ; preds = %if.end51
+  unreachable
+
+if.end63:                                         ; preds = %if.end51
+  unreachable
+}
+
+declare void @bar() local_unnamed_addr #0
+
+attributes #0 = { nounwind }