From: Evan Cheng <evan.cheng@apple.com>
Date: Tue, 21 Jul 2009 00:31:12 +0000 (+0000)
Subject: Fix ARM isle code that optimize multiply by constants which are power-of-2 +/- 1.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=af9e7a7c20d541cfaaaed9dfa21046ac6652cc03;p=oota-llvm.git

Fix ARM isle code that optimize multiply by constants which are power-of-2 +/- 1.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76520 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 95ed887ef6d..c943baf75d9 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -949,26 +949,36 @@ SDNode *ARMDAGToDAGISel::Select(SDValue Op) {
       unsigned RHSV = C->getZExtValue();
       if (!RHSV) break;
       if (isPowerOf2_32(RHSV-1)) {  // 2^n+1?
+        unsigned ShImm = Log2_32(RHSV-1);
+        if (ShImm >= 32)
+          break;
         SDValue V = Op.getOperand(0);
-        unsigned ShImm = ARM_AM::getSORegOpc(ARM_AM::lsl, Log2_32(RHSV-1));
-        SDValue Ops[] = { V, V, CurDAG->getRegister(0, MVT::i32),
-                            CurDAG->getTargetConstant(ShImm, MVT::i32),
-                            getAL(CurDAG), CurDAG->getRegister(0, MVT::i32),
-                            CurDAG->getRegister(0, MVT::i32) };
-        return CurDAG->SelectNodeTo(N, (Subtarget->isThumb() &&
-                                        Subtarget->hasThumb2()) ? 
-                                    ARM::t2ADDrs : ARM::ADDrs, MVT::i32, Ops, 7);
+        ShImm = ARM_AM::getSORegOpc(ARM_AM::lsl, ShImm);
+        SDValue ShImmOp = CurDAG->getConstant(ShImm, MVT::i32);
+        SDValue Reg0 = CurDAG->getRegister(0, MVT::i32);
+        if (Subtarget->isThumb() && Subtarget->hasThumb2()) {
+          SDValue Ops[] = { V, V, ShImmOp, getAL(CurDAG), Reg0, Reg0 };
+          return CurDAG->SelectNodeTo(N, ARM::t2ADDrs, MVT::i32, Ops, 6);
+        } else {
+          SDValue Ops[] = { V, V, Reg0, ShImmOp, getAL(CurDAG), Reg0, Reg0 };
+          return CurDAG->SelectNodeTo(N, ARM::ADDrs, MVT::i32, Ops, 7);
+        }
       }
       if (isPowerOf2_32(RHSV+1)) {  // 2^n-1?
+        unsigned ShImm = Log2_32(RHSV+1);
+        if (ShImm >= 32)
+          break;
         SDValue V = Op.getOperand(0);
-        unsigned ShImm = ARM_AM::getSORegOpc(ARM_AM::lsl, Log2_32(RHSV+1));
-        SDValue Ops[] = { V, V, CurDAG->getRegister(0, MVT::i32),
-                            CurDAG->getTargetConstant(ShImm, MVT::i32),
-                            getAL(CurDAG), CurDAG->getRegister(0, MVT::i32),
-                            CurDAG->getRegister(0, MVT::i32) };
-        return CurDAG->SelectNodeTo(N, (Subtarget->isThumb() &&
-                                        Subtarget->hasThumb2()) ? 
-                                    ARM::t2RSBrs : ARM::RSBrs, MVT::i32, Ops, 7);
+        ShImm = ARM_AM::getSORegOpc(ARM_AM::lsl, ShImm);
+        SDValue ShImmOp = CurDAG->getConstant(ShImm, MVT::i32);
+        SDValue Reg0 = CurDAG->getRegister(0, MVT::i32);
+        if (Subtarget->isThumb() && Subtarget->hasThumb2()) {
+          SDValue Ops[] = { V, V, ShImmOp, getAL(CurDAG), Reg0 };
+          return CurDAG->SelectNodeTo(N, ARM::t2RSBrs, MVT::i32, Ops, 5);
+        } else {
+          SDValue Ops[] = { V, V, Reg0, ShImmOp, getAL(CurDAG), Reg0, Reg0 };
+          return CurDAG->SelectNodeTo(N, ARM::RSBrs, MVT::i32, Ops, 7);
+        }
       }
     }
     break;
diff --git a/test/CodeGen/ARM/mul_const.ll b/test/CodeGen/ARM/mul_const.ll
new file mode 100644
index 00000000000..f5ace1852a4
--- /dev/null
+++ b/test/CodeGen/ARM/mul_const.ll
@@ -0,0 +1,17 @@
+; RUN: llvm-as < %s | llc -march=arm | FileCheck %s
+
+define i32 @t1(i32 %v) nounwind readnone {
+entry:
+; CHECK: t1:
+; CHECK: add r0, r0, r0, lsl #3
+	%0 = mul i32 %v, 9
+	ret i32 %0
+}
+
+define i32 @t2(i32 %v) nounwind readnone {
+entry:
+; CHECK: t2:
+; CHECK: rsb r0, r0, r0, lsl #3
+	%0 = mul i32 %v, 7
+	ret i32 %0
+}
diff --git a/test/CodeGen/Thumb2/mul_const.ll b/test/CodeGen/Thumb2/mul_const.ll
new file mode 100644
index 00000000000..ca0ede45eb2
--- /dev/null
+++ b/test/CodeGen/Thumb2/mul_const.ll
@@ -0,0 +1,18 @@
+; RUN: llvm-as < %s | llc -march=thumb -mattr=+thumb2 | FileCheck %s
+; rdar://7069502
+
+define i32 @t1(i32 %v) nounwind readnone {
+entry:
+; CHECK: t1:
+; CHECK: add r0, r0, r0, lsl #3
+	%0 = mul i32 %v, 9
+	ret i32 %0
+}
+
+define i32 @t2(i32 %v) nounwind readnone {
+entry:
+; CHECK: t2:
+; CHECK: rsb r0, r0, r0, lsl #3
+	%0 = mul i32 %v, 7
+	ret i32 %0
+}