Also match negative offsets for addrmode3 and addrmode5.

Math is hard, and isScaledConstantInRange() always returned false for
negative constants.  It was doing unsigned division of negative numbers
before casting back to signed.

llvm-svn: 140425

2 files changed, 20 insertions, 2 deletions

diff --git a/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp b/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
index e05589eb5ba..66fc754dd01 100644
--- a/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -305,10 +305,10 @@ static bool isOpcWithIntImmediate(SDNode *N, unsigned Opc, unsigned& Imm) {
 /// (N * Scale) where (N in [\arg RangeMin, \arg RangeMax).
 ///
 /// \param ScaledConstant [out] - On success, the pre-scaled constant value.
-static bool isScaledConstantInRange(SDValue Node, unsigned Scale,
+static bool isScaledConstantInRange(SDValue Node, int Scale,
                                     int RangeMin, int RangeMax,
                                     int &ScaledConstant) {
-  assert(Scale && "Invalid scale!");
+  assert(Scale > 0 && "Invalid scale!");
 
   // Check that this is a constant.
   const ConstantSDNode *C = dyn_cast<ConstantSDNode>(Node);
diff --git a/llvm/test/CodeGen/ARM/fpmem.ll b/llvm/test/CodeGen/ARM/fpmem.ll
index c3cff18c959..38339334b44 100644
--- a/llvm/test/CodeGen/ARM/fpmem.ll
+++ b/llvm/test/CodeGen/ARM/fpmem.ll
@@ -14,6 +14,24 @@ define float @f2(float* %v, float %u) {
         ret float %tmp1
 }
 
+define float @f2offset(float* %v, float %u) {
+; CHECK: f2offset:
+; CHECK: vldr.32{{.*}}, #4]
+        %addr = getelementptr float* %v, i32 1
+        %tmp = load float* %addr
+        %tmp1 = fadd float %tmp, %u
+        ret float %tmp1
+}
+
+define float @f2noffset(float* %v, float %u) {
+; CHECK: f2noffset:
+; CHECK: vldr.32{{.*}}, #-4]
+        %addr = getelementptr float* %v, i32 -1
+        %tmp = load float* %addr
+        %tmp1 = fadd float %tmp, %u
+        ret float %tmp1
+}
+
 define void @f3(float %a, float %b, float* %v) {
 ; CHECK: f3:
 ; CHECK: vstr.32{{.*}}[