From a9688c4b5769be7a6a89350888b3173c97fe87ed Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Sat, 11 Dec 2010 04:11:38 +0000
Subject: [PATCH] (or (and (shl A, #shamt), mask), B) => ARMbfi B, A, ~mask
 where lsb(mask) == #shamt. rdar://8752056

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121606 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMISelLowering.cpp | 35 ++++++++++++++++++++++++------
 lib/Target/ARM/ARMInstrInfo.td     | 20 ++++++++---------
 test/CodeGen/ARM/bfi.ll            | 15 +++++++++++--
 test/CodeGen/Thumb2/bfi.ll         | 11 ++++++++++
 4 files changed, 62 insertions(+), 19 deletions(-)

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 22efa48709e..f4a12ed77c5 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -4727,16 +4727,37 @@ static SDValue PerformORCombine(SDNode *N,
   // Case (1): or (and A, mask), val => ARMbfi A, val, mask
   if ((C = dyn_cast<ConstantSDNode>(N1))) {
     unsigned Val = C->getZExtValue();
-    if (!ARM::isBitFieldInvertedMask(Mask) || (Val & ~Mask) != Val)
+    if ((Val & ~Mask) != Val)
       return SDValue();
-    Val >>= CountTrailingZeros_32(~Mask);
 
-    Res = DAG.getNode(ARMISD::BFI, DL, VT, N0.getOperand(0),
-                      DAG.getConstant(Val, MVT::i32),
-                      DAG.getConstant(Mask, MVT::i32));
+    if (ARM::isBitFieldInvertedMask(Mask)) {
+      Val >>= CountTrailingZeros_32(~Mask);
 
-    // Do not add new nodes to DAG combiner worklist.
-    DCI.CombineTo(N, Res, false);
+      Res = DAG.getNode(ARMISD::BFI, DL, VT, N0.getOperand(0),
+                        DAG.getConstant(Val, MVT::i32),
+                        DAG.getConstant(Mask, MVT::i32));
+
+      // Do not add new nodes to DAG combiner worklist.
+      DCI.CombineTo(N, Res, false);
+    } else if (N0.getOperand(0).getOpcode() == ISD::SHL &&
+               isa<ConstantSDNode>(N0.getOperand(0).getOperand(1)) &&
+               ARM::isBitFieldInvertedMask(~Mask)) {
+      // Case (3): or (and (shl A, #shamt), mask), B => ARMbfi B, A, ~mask
+      // where lsb(mask) == #shamt
+      SDValue ShAmt = N0.getOperand(0).getOperand(1);
+      unsigned ShAmtC = cast<ConstantSDNode>(ShAmt)->getZExtValue();
+      unsigned LSB = CountTrailingZeros_32(Mask);
+      if (ShAmtC != LSB)
+        return SDValue();
+      //unsigned Width = (32 - CountLeadingZeros_32(Mask)) - LSB;
+
+      Res = DAG.getNode(ARMISD::BFI, DL, VT, N1,
+                        N0.getOperand(0).getOperand(0),
+                        DAG.getConstant(~Mask, MVT::i32));
+
+      // Do not add new nodes to DAG combiner worklist.
+      DCI.CombineTo(N, Res, false);
+    }
   } else if (N1.getOpcode() == ISD::AND) {
     // case (2) or (and A, mask), (and B, mask2) => ARMbfi A, (lsr B, amt), mask
     C = dyn_cast<ConstantSDNode>(N1.getOperand(1));
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 4da445f5882..f93d8ff2e30 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -225,16 +225,6 @@ def sext_16_node : PatLeaf<(i32 GPR:$a), [{
   return CurDAG->ComputeNumSignBits(SDValue(N,0)) >= 17;
 }]>;
 
-/// bf_inv_mask_imm predicate - An AND mask to clear an arbitrary width bitfield
-/// e.g., 0xf000ffff
-def bf_inv_mask_imm : Operand<i32>,
-                      PatLeaf<(imm), [{
-  return ARM::isBitFieldInvertedMask(N->getZExtValue());
-}] > {
-  let EncoderMethod = "getBitfieldInvertedMaskOpValue";
-  let PrintMethod = "printBitfieldInvMaskImmOperand";
-}
-
 /// Split a 32-bit immediate into two 16 bit parts.
 def hi16 : SDNodeXForm<imm, [{
   return CurDAG->getTargetConstant((uint32_t)N->getZExtValue() >> 16, MVT::i32);
@@ -462,6 +452,16 @@ def movt_imm : Operand<i32> {
   let EncoderMethod = "getMovtImmOpValue";
 }
 
+/// bf_inv_mask_imm predicate - An AND mask to clear an arbitrary width bitfield
+/// e.g., 0xf000ffff
+def bf_inv_mask_imm : Operand<i32>,
+                      PatLeaf<(imm), [{
+  return ARM::isBitFieldInvertedMask(N->getZExtValue());
+}] > {
+  let EncoderMethod = "getBitfieldInvertedMaskOpValue";
+  let PrintMethod = "printBitfieldInvMaskImmOperand";
+}
+
 // Define ARM specific addressing modes.
 
 
diff --git a/test/CodeGen/ARM/bfi.ll b/test/CodeGen/ARM/bfi.ll
index 0e36283a39f..157c90c7531 100644
--- a/test/CodeGen/ARM/bfi.ll
+++ b/test/CodeGen/ARM/bfi.ll
@@ -16,7 +16,7 @@ entry:
   ret void
 }
 
-define i32 @f2(i32 %A, i32 %B) nounwind readnone optsize {
+define i32 @f2(i32 %A, i32 %B) nounwind {
 entry:
 ; CHECK: f2
 ; CHECK: lsr{{.*}}#7
@@ -27,7 +27,7 @@ entry:
   ret i32 %or
 }
 
-define i32 @f3(i32 %A, i32 %B) nounwind readnone optsize {
+define i32 @f3(i32 %A, i32 %B) nounwind {
 entry:
 ; CHECK: f3
 ; CHECK: lsr{{.*}} #7
@@ -38,3 +38,14 @@ entry:
   %or = or i32 %and2, %and                        ; <i32> [#uses=1]
   ret i32 %or
 }
+
+; rdar://8752056
+define i32 @f4(i32 %a) nounwind {
+; CHECK: f4
+; CHECK: movw r1, #3137
+; CHECK: bfi r1, r0, #15, #5
+  %1 = shl i32 %a, 15
+  %ins7 = and i32 %1, 1015808
+  %ins12 = or i32 %ins7, 3137
+  ret i32 %ins12
+}
diff --git a/test/CodeGen/Thumb2/bfi.ll b/test/CodeGen/Thumb2/bfi.ll
index 22473bb35a0..6fb2fc888d9 100644
--- a/test/CodeGen/Thumb2/bfi.ll
+++ b/test/CodeGen/Thumb2/bfi.ll
@@ -38,3 +38,14 @@ entry:
   %or = or i32 %and2, %and                        ; <i32> [#uses=1]
   ret i32 %or
 }
+
+; rdar://8752056
+define i32 @f4(i32 %a) nounwind {
+; CHECK: f4
+; CHECK: movw r1, #3137
+; CHECK: bfi r1, r0, #15, #5
+  %1 = shl i32 %a, 15
+  %ins7 = and i32 %1, 1015808
+  %ins12 = or i32 %ins7, 3137
+  ret i32 %ins12
+}