[llvm] r276624 - [ARM] Enable ISel of SMMLS for ARM and Thumb2

[Sam Parker via llvm-commits]

Author: sam_parker
Date: Mon Jul 25 04:20:20 2016
New Revision: 276624

URL: http://llvm.org/viewvc/llvm-project?rev=276624&view=rev
Log:
[ARM] Enable ISel of SMMLS for ARM and Thumb2

Use ISelDAGToDAG to recognise the SMMLS instruction pattern.

Differential Revision: https://reviews.llvm.org/D22562


Modified:
    llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp
    llvm/trunk/lib/Target/ARM/ARMInstrThumb2.td
    llvm/trunk/test/CodeGen/ARM/smml.ll

Modified: llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp?rev=276624&r1=276623&r2=276624&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp Mon Jul 25 04:20:20 2016
@@ -3037,6 +3037,36 @@ void ARMDAGToDAGISel::Select(SDNode *N)
       return;
     }
   }
+  case ARMISD::SUBE: {
+    if (!Subtarget->hasV6Ops())
+      break;
+    // Look for a pattern to match SMMLS
+    // (sube a, (smul_loHi a, b), (subc 0, (smul_LOhi(a, b))))
+    if (N->getOperand(1).getOpcode() != ISD::SMUL_LOHI ||
+        N->getOperand(2).getOpcode() != ARMISD::SUBC)
+      break;
+
+    if (Subtarget->isThumb())
+      assert(Subtarget->hasThumb2() &&
+             "This pattern should not be generated for Thumb");
+
+    SDValue SmulLoHi = N->getOperand(1);
+    SDValue Subc = N->getOperand(2);
+    auto *Zero = dyn_cast<ConstantSDNode>(Subc.getOperand(0));
+
+    if (!Zero || Zero->getZExtValue() != 0 ||
+        Subc.getOperand(1) != SmulLoHi.getValue(0) ||
+        N->getOperand(1) != SmulLoHi.getValue(1) ||
+        N->getOperand(2) != Subc.getValue(1))
+      break;
+
+    unsigned Opc = Subtarget->isThumb2() ? ARM::t2SMMLS : ARM::SMMLS;
+    SDValue Ops[] = { SmulLoHi.getOperand(0), SmulLoHi.getOperand(1),
+                      N->getOperand(0), getAL(CurDAG, dl),
+                      CurDAG->getRegister(0, MVT::i32) };
+    ReplaceNode(N, CurDAG->getMachineNode(Opc, dl, MVT::i32, Ops));
+    return;
+  }
   case ISD::LOAD: {
     if (Subtarget->isThumb() && Subtarget->hasThumb2()) {
       if (tryT2IndexedLoad(N))

Modified: llvm/trunk/lib/Target/ARM/ARMInstrThumb2.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMInstrThumb2.td?rev=276624&r1=276623&r2=276624&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMInstrThumb2.td (original)
+++ llvm/trunk/lib/Target/ARM/ARMInstrThumb2.td Mon Jul 25 04:20:20 2016
@@ -2604,12 +2604,11 @@ class T2FourRegSMMLA<bits<3> op22_20, bi
   let Inst{7-4} = op7_4;
 }
 
-def t2SMMLA : T2FourRegSMMLA<0b101, 0b0000, "smmla",
+def t2SMMLA :   T2FourRegSMMLA<0b101, 0b0000, "smmla",
                 [(set rGPR:$Rd, (add (mulhs rGPR:$Rm, rGPR:$Rn), rGPR:$Ra))]>;
-def t2SMMLAR: T2FourRegSMMLA<0b101, 0b0001, "smmlar", []>;
-def t2SMMLS: T2FourRegSMMLA<0b110, 0b0000, "smmls",
-                [(set rGPR:$Rd, (sub rGPR:$Ra, (mulhs rGPR:$Rn, rGPR:$Rm)))]>;
-def t2SMMLSR:T2FourRegSMMLA<0b110, 0b0001, "smmlsr", []>;
+def t2SMMLAR:   T2FourRegSMMLA<0b101, 0b0001, "smmlar", []>;
+def t2SMMLS:    T2FourRegSMMLA<0b110, 0b0000, "smmls", []>;
+def t2SMMLSR:   T2FourRegSMMLA<0b110, 0b0001, "smmlsr", []>;
 
 class T2ThreeRegSMUL<bits<3> op22_20, bits<2> op5_4, string opc,
                      list<dag> pattern>

Modified: llvm/trunk/test/CodeGen/ARM/smml.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/smml.ll?rev=276624&r1=276623&r2=276624&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/smml.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/smml.ll Mon Jul 25 04:20:20 2016
@@ -1,8 +1,20 @@
-; RUN: llc -mtriple=arm-eabi -mcpu=cortex-a8 %s -o - | FileCheck %s
+; RUN: llc -mtriple=arm-eabi %s -o - | FileCheck %s -check-prefix=CHECK
+; RUN: llc -mtriple=armv6-eabi %s -o - | FileCheck %s -check-prefix=CHECK-V6
+; RUN: llc -mtriple=armv7-eabi %s -o - | FileCheck %s -check-prefix=CHECK-V7
+; RUN: llc -mtriple=thumb-eabi %s -o - | FileCheck %s -check-prefix=CHECK-THUMB
+; RUN: llc -mtriple=thumbv6-eabi %s -o - | FileCheck %s -check-prefix=CHECK-THUMB
+; RUN: llc -mtriple=thumbv6t2-eabi %s -o - | FileCheck %s -check-prefix=CHECK-THUMBV6T2
+; RUN: llc -mtriple=thumbv7-eabi %s -o - | FileCheck %s -check-prefix=CHECK-THUMBV7
 
-define i32 @f(i32 %a, i32 %b, i32 %c) nounwind readnone ssp {
+define i32 @Test0(i32 %a, i32 %b, i32 %c) nounwind readnone ssp {
 entry:
+; CHECK-LABEL: Test0
 ; CHECK-NOT: smmls
+; CHECK-V6-NOT: smmls
+; CHECK-V7-NOT: smmls
+; CHECK_THUMB-NOT: smmls
+; CHECK-THUMBV6T2-NOT: smmls
+; CHECK-THUMBV7-NOT: smmls
   %conv4 = zext i32 %a to i64
   %conv1 = sext i32 %b to i64
   %conv2 = sext i32 %c to i64
@@ -12,3 +24,23 @@ entry:
   %conv3 = trunc i64 %sub to i32
   ret i32 %conv3
 }
+
+define i32 @Test1(i32 %a, i32 %b, i32 %c) {
+;CHECK-LABEL: Test1
+;CHECK-NOT: smmls
+;CHECK-THUMB-NOT: smmls
+;CHECK-V6: smmls r0, [[Rn:r[1-2]]], [[Rm:r[1-2]]], r0
+;CHECK-V7: smmls r0, [[Rn:r[1-2]]], [[Rm:r[1-2]]], r0
+;CHECK-THUMBV6T2: smmls r0, [[Rn:r[1-2]]], [[Rm:r[1-2]]], r0
+;CHECK-THUMBV7: smmls r0, [[Rn:r[1-2]]], [[Rm:r[1-2]]], r0
+entry:
+  %conv = sext i32 %b to i64
+  %conv1 = sext i32 %c to i64
+  %mul = mul nsw i64 %conv1, %conv
+  %conv26 = zext i32 %a to i64
+  %shl = shl nuw i64 %conv26, 32
+  %sub = sub nsw i64 %shl, %mul
+  %shr7 = lshr i64 %sub, 32
+  %conv3 = trunc i64 %shr7 to i32
+  ret i32 %conv3
+}