make gep matching in fastisel match the base of the gep as a

register if it isn't possible to match the indexes *and* the base.
This fixes some fast isel rejects of load instructions on oggenc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97739 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 1 deletions

diff --git a/lib/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index 17366ee..c6da5cc 100644
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -425,10 +425,17 @@ bool X86FastISel::X86SelectAddress(Value *V, X86AddressMode &AM) {
       break;
     // Ok, the GEP indices were covered by constant-offset and scaled-index
     // addressing. Update the address state and move on to examining the base.
+    X86AddressMode SavedAM = AM;
     AM.IndexReg = IndexReg;
     AM.Scale = Scale;
     AM.Disp = (uint32_t)Disp;
-    return X86SelectAddress(U->getOperand(0), AM);
+    if (X86SelectAddress(U->getOperand(0), AM))
+      return true;
+    
+    // If we couldn't merge the sub value into this addr mode, revert back to
+    // our address and just match the value instead of completely failing.
+    AM = SavedAM;
+    break;
   unsupported_gep:
     // Ok, the GEP indices weren't all covered.
     break;