From 40efc251cd7a52dd2375ec95ee38b1be4572178f Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Fri, 24 Jul 2009 19:31:03 +0000
Subject: [PATCH] Disable my constant island pass optimization (to make use
 soimm more effectively). It caused infinite looping on lencod.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76995 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMConstantIslandPass.cpp | 6 ++----
 lib/Target/ARM/README.txt                | 5 +++++
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/lib/Target/ARM/ARMConstantIslandPass.cpp b/lib/Target/ARM/ARMConstantIslandPass.cpp
index 1f584d4e3ef..48db39b623a 100644
--- a/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -696,13 +696,11 @@ bool ARMConstantIslands::OffsetIsInRange(unsigned UserOffset,
     // User before the Trial.
     if (TrialOffset - UserOffset <= MaxDisp)
       return true;
-    if (IsSoImm && ARM_AM::getSOImmVal(TrialOffset - UserOffset) != -1)
-      return true;
+    // FIXME: Make use full range of soimm values.
   } else if (NegativeOK) {
     if (UserOffset - TrialOffset <= MaxDisp)
       return true;
-    if (IsSoImm && ARM_AM::getSOImmVal(~(TrialOffset - UserOffset)) != -1)
-      return true;
+    // FIXME: Make use full range of soimm values.
   }
   return false;
 }
diff --git a/lib/Target/ARM/README.txt b/lib/Target/ARM/README.txt
index 3e8c54a05a8..a587a2bf7ea 100644
--- a/lib/Target/ARM/README.txt
+++ b/lib/Target/ARM/README.txt
@@ -541,3 +541,8 @@ while ARMConstantIslandPass only need to worry about LDR (literal).
 //===---------------------------------------------------------------------===//
 
 We need to fix constant isel for ARMv6t2 to use MOVT.
+
+//===---------------------------------------------------------------------===//
+
+Constant island pass should make use of full range SoImm values for LEApcrel.
+Be careful though as the last attempt caused infinite looping on lencod.