IR: compare type attributes deeply when looking into functions.

FunctionComparator attempts to produce a stable comparison of two Function
instances by looking at all available properties. Since ByVal attributes now
contain a Type pointer, they are not trivially ordered and FunctionComparator
should use its own Type comparison logic to sort them.

llvm-svn: 364523

1 files changed, 13 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/FunctionComparator.cpp b/llvm/lib/Transforms/Utils/FunctionComparator.cpp
index 5c400cec573..a9b28754c8e 100644
--- a/llvm/lib/Transforms/Utils/FunctionComparator.cpp
+++ b/llvm/lib/Transforms/Utils/FunctionComparator.cpp
@@ -113,6 +113,19 @@ int FunctionComparator::cmpAttrs(const AttributeList L,
     for (; LI != LE && RI != RE; ++LI, ++RI) {
       Attribute LA = *LI;
       Attribute RA = *RI;
+      if (LA.isTypeAttribute() && RA.isTypeAttribute()) {
+        if (LA.getKindAsEnum() != RA.getKindAsEnum())
+          return cmpNumbers(LA.getKindAsEnum(), RA.getKindAsEnum());
+
+        Type *TyL = LA.getValueAsType();
+        Type *TyR = RA.getValueAsType();
+        if (TyL && TyR)
+          return cmpTypes(TyL, TyR);
+
+        // Two pointers, at least one null, so the comparison result is
+        // independent of the value of a real pointer.
+        return cmpNumbers((uint64_t)TyL, (uint64_t)TyR);
+      }
       if (LA < RA)
         return -1;
       if (RA < LA)