Fix PR2590 by making PatternSortingPredicate actually be

ordered correctly.  Previously it would get in trouble when
two patterns were too similar and give them nondet ordering.
We force this by using the record ID order as a fallback.

The testsuite diff is due to alpha patterns being ordered
slightly differently, the change is a semantic noop afaict:

< 	lda $0,-100($16)
---
> 	subq $16,100,$0



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97509 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 2 deletions

diff --git a/utils/TableGen/DAGISelEmitter.cpp b/utils/TableGen/DAGISelEmitter.cpp
index 8816c9c0e7..03a12cd13d 100644
--- a/utils/TableGen/DAGISelEmitter.cpp
+++ b/utils/TableGen/DAGISelEmitter.cpp
@@ -174,8 +174,14 @@ struct PatternSortingPredicate {
     if (LHSCost < RHSCost) return true;
     if (LHSCost > RHSCost) return false;
     
-    return getResultPatternSize(LHS->getDstPattern(), CGP) <
-           getResultPatternSize(RHS->getDstPattern(), CGP);
+    unsigned LHSPatSize = getResultPatternSize(LHS->getDstPattern(), CGP);
+    unsigned RHSPatSize = getResultPatternSize(RHS->getDstPattern(), CGP);
+    if (LHSPatSize < RHSPatSize) return true;
+    if (LHSPatSize > RHSPatSize) return false;
+    
+    // Sort based on the UID of the pattern, giving us a deterministic ordering.
+    assert(LHS->ID != RHS->ID);
+    return LHS->ID < RHS->ID;
   }
 };
 }