[llvm-commits] [llvm] r149588 - in /llvm/trunk: lib/CodeGen/LiveInterval.cpp test/CodeGen/Generic/2012-02-01-CoalescerBug.ll

[Lang Hames]

Author: lhames
Date: Wed Feb  1 23:37:34 2012
New Revision: 149588

URL: http://llvm.org/viewvc/llvm-project?rev=149588&view=rev
Log:
PR11868. The previous loop in LiveIntervals::join would sometimes fall over if
more than two adjacent ranges needed to be merged. The new version should be
able to handle an arbitrary sequence of adjancent ranges.

Added:
    llvm/trunk/test/CodeGen/Generic/2012-02-01-CoalescerBug.ll
Modified:
    llvm/trunk/lib/CodeGen/LiveInterval.cpp

Modified: llvm/trunk/lib/CodeGen/LiveInterval.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveInterval.cpp?rev=149588&r1=149587&r2=149588&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveInterval.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveInterval.cpp Wed Feb  1 23:37:34 2012
@@ -389,29 +389,30 @@
   // now.
   if (MustMapCurValNos) {
     // Map the first live range.
+
     iterator OutIt = begin();
     OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]];
-    ++OutIt;
-    for (iterator I = OutIt, E = end(); I != E; ++I) {
-      OutIt->valno = NewVNInfo[LHSValNoAssignments[I->valno->id]];
+    for (iterator I = next(OutIt), E = end(); I != E; ++I) {
+      VNInfo* nextValNo = NewVNInfo[LHSValNoAssignments[I->valno->id]];
+      assert(nextValNo != 0 && "Huh?");
 
       // If this live range has the same value # as its immediate predecessor,
       // and if they are neighbors, remove one LiveRange.  This happens when we
-      // have [0,3:0)[4,7:1) and map 0/1 onto the same value #.
-      if (OutIt->valno == (OutIt-1)->valno && (OutIt-1)->end == OutIt->start) {
-        (OutIt-1)->end = OutIt->end;
+      // have [0,4:0)[4,7:1) and map 0/1 onto the same value #.
+      if (OutIt->valno == nextValNo && OutIt->end == I->start) {
+        OutIt->end = I->end;
       } else {
-        if (I != OutIt) {
+        // Didn't merge. Move OutIt to the next interval,
+        ++OutIt;
+        OutIt->valno = nextValNo;
+        if (OutIt != I) {
           OutIt->start = I->start;
           OutIt->end = I->end;
         }
-
-        // Didn't merge, on to the next one.
-        ++OutIt;
       }
     }
-
     // If we merge some live ranges, chop off the end.
+    ++OutIt;
     ranges.erase(OutIt, end());
   }
 

Added: llvm/trunk/test/CodeGen/Generic/2012-02-01-CoalescerBug.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Generic/2012-02-01-CoalescerBug.ll?rev=149588&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Generic/2012-02-01-CoalescerBug.ll (added)
+++ llvm/trunk/test/CodeGen/Generic/2012-02-01-CoalescerBug.ll Wed Feb  1 23:37:34 2012
@@ -0,0 +1,26 @@
+; RUN: llc -verify-coalescing < %s
+; PR11868
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:64:128-a0:0:64-n32-S64"
+target triple = "armv7-none-linux-gnueabi"
+
+%0 = type { <4 x float> }
+%1 = type { <4 x float> }
+
+ at foo = external global %0, align 16
+
+define arm_aapcs_vfpcc void @bar(float, i1 zeroext, i1 zeroext) nounwind {
+  %4 = load <4 x float>* getelementptr inbounds (%0* @foo, i32 0, i32 0), align 16
+  %5 = extractelement <4 x float> %4, i32 0
+  %6 = extractelement <4 x float> %4, i32 1
+  %7 = extractelement <4 x float> %4, i32 2
+  %8 = insertelement <4 x float> undef, float %5, i32 0
+  %9 = insertelement <4 x float> %8, float %6, i32 1
+  %10 = insertelement <4 x float> %9, float %7, i32 2
+  %11 = insertelement <4 x float> %10, float 0.000000e+00, i32 3
+  store <4 x float> %11, <4 x float>* undef, align 16 
+  call arm_aapcs_vfpcc  void @baz(%1* undef, float 0.000000e+00) nounwind
+  ret void
+}
+
+declare arm_aapcs_vfpcc void @baz(%1*, float)