Add DAG combine for shl + add of constants.

Do
 (shl (add x, c1), c2) -> (add (shl x, c2), c1 << c2)

This is already done for multiplies, but since multiplies
by powers of two are turned into shifts, we also need
to handle it here.

This might want checks for isLegalAddImmediate to avoid
transforming an add of a legal immediate with one that isn't.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217610 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index c29200a549ecdc37523cd06d5dd866a8d49e2ca5..8a09838873a598c3b59d0159f6eb4ddf46de176e 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1517,28 +1517,6 @@ SDValue DAGCombiner::visitMERGE_VALUES(SDNode *N) {
   return SDValue(N, 0);   // Return N so it doesn't get rechecked!
 }
 
-static
-SDValue combineShlAddConstant(SDLoc DL, SDValue N0, SDValue N1,
-                              SelectionDAG &DAG) {
-  EVT VT = N0.getValueType();
-  SDValue N00 = N0.getOperand(0);
-  SDValue N01 = N0.getOperand(1);
-  ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N01);
-
-  if (N01C && N00.getOpcode() == ISD::ADD && N00.getNode()->hasOneUse() &&
-      isa<ConstantSDNode>(N00.getOperand(1))) {
-    // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), )
-    N0 = DAG.getNode(ISD::ADD, SDLoc(N0), VT,
-                     DAG.getNode(ISD::SHL, SDLoc(N00), VT,
-                                 N00.getOperand(0), N01),
-                     DAG.getNode(ISD::SHL, SDLoc(N01), VT,
-                                 N00.getOperand(1), N01));
-    return DAG.getNode(ISD::ADD, DL, VT, N0, N1);
-  }
-
-  return SDValue();
-}
-
 SDValue DAGCombiner::visitADD(SDNode *N) {
   SDValue N0 = N->getOperand(0);
   SDValue N1 = N->getOperand(1);
@@ -1655,16 +1633,6 @@ SDValue DAGCombiner::visitADD(SDNode *N) {
     }
   }
 
-  // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), )
-  if (N0.getOpcode() == ISD::SHL && N0.getNode()->hasOneUse()) {
-    SDValue Result = combineShlAddConstant(SDLoc(N), N0, N1, DAG);
-    if (Result.getNode()) return Result;
-  }
-  if (N1.getOpcode() == ISD::SHL && N1.getNode()->hasOneUse()) {
-    SDValue Result = combineShlAddConstant(SDLoc(N), N1, N0, DAG);
-    if (Result.getNode()) return Result;
-  }
-
   // fold (add x, shl(0 - y, n)) -> sub(x, shl(y, n))
   if (N1.getOpcode() == ISD::SHL &&
       N1.getOperand(0).getOpcode() == ISD::SUB)
@@ -4185,6 +4153,18 @@ SDValue DAGCombiner::visitSHL(SDNode *N) {
                        HiBitsMask);
   }
 
+  // fold (shl (add x, c1), c2) -> (add (shl x, c2), c1 << c2)
+  // Variant of version done on multiply, except mul by a power of 2 is turned
+  // into a shift.
+  APInt Val;
+  if (N1C && N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse() &&
+      (isa<ConstantSDNode>(N0.getOperand(1)) ||
+       isConstantSplatVector(N0.getOperand(1).getNode(), Val))) {
+    SDValue Shl0 = DAG.getNode(ISD::SHL, SDLoc(N0), VT, N0.getOperand(0), N1);
+    SDValue Shl1 = DAG.getNode(ISD::SHL, SDLoc(N1), VT, N0.getOperand(1), N1);
+    return DAG.getNode(ISD::ADD, SDLoc(N), VT, Shl0, Shl1);
+  }
+
   if (N1C) {
     SDValue NewSHL = visitShiftByConstant(N, N1C);
     if (NewSHL.getNode())

diff --git a/test/CodeGen/AArch64/arm64-shifted-sext.ll b/test/CodeGen/AArch64/arm64-shifted-sext.ll
index b7b4e5de1d5c1ef9f8a635836a6e25a9971e6261..71f15b1222b2b8008ba1c3ab25ffe9c6f25afc3e 100644 (file)
--- a/test/CodeGen/AArch64/arm64-shifted-sext.ll
+++ b/test/CodeGen/AArch64/arm64-shifted-sext.ll
@@ -166,8 +166,8 @@ entry:
 define i32 @extendedLeftShiftshortTointBy16(i16 signext %a) nounwind readnone ssp {
 entry:
 ; CHECK-LABEL: extendedLeftShiftshortTointBy16:
-; CHECK: add [[REG:w[0-9]+]], w0, #1
-; CHECK: lsl w0, [[REG]], #16
+; CHECK: lsl [[REG:w[0-9]+]], w0, #16
+; CHECK: add w0, [[REG]], #16, lsl #12
   %inc = add i16 %a, 1
   %conv2 = zext i16 %inc to i32
   %shl = shl nuw i32 %conv2, 16

diff --git a/test/CodeGen/R600/shl_add_constant.ll b/test/CodeGen/R600/shl_add_constant.ll
new file mode 100644 (file)
index 0000000..60f35d7
--- /dev/null
+++ b/test/CodeGen/R600/shl_add_constant.ll
@@ -0,0 +1,90 @@
+; RUN: llc -march=r600 -mcpu=SI -verify-machineinstrs < %s | FileCheck -check-prefix=SI %s
+
+declare i32 @llvm.r600.read.tidig.x() #1
+
+; Test with inline immediate
+
+; FUNC-LABEL: @shl_2_add_9_i32
+; SI: V_LSHLREV_B32_e32  [[REG:v[0-9]+]], 2, {{v[0-9]+}}
+; SI: V_ADD_I32_e32 [[RESULT:v[0-9]+]], 36, [[REG]]
+; SI: BUFFER_STORE_DWORD [[RESULT]]
+; SI: S_ENDPGM
+define void @shl_2_add_9_i32(i32 addrspace(1)* %out, i32 addrspace(1)* %in) #0 {
+  %tid.x = tail call i32 @llvm.r600.read.tidig.x() #1
+  %ptr = getelementptr i32 addrspace(1)* %in, i32 %tid.x
+  %val = load i32 addrspace(1)* %ptr, align 4
+  %add = add i32 %val, 9
+  %result = shl i32 %add, 2
+  store i32 %result, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
+; FUNC-LABEL: @shl_2_add_9_i32_2_add_uses
+; SI-DAG: V_ADD_I32_e32 [[ADDREG:v[0-9]+]], 9, {{v[0-9]+}}
+; SI-DAG: V_LSHLREV_B32_e32 [[SHLREG:v[0-9]+]], 2, {{v[0-9]+}}
+; SI-DAG: BUFFER_STORE_DWORD [[ADDREG]]
+; SI-DAG: BUFFER_STORE_DWORD [[SHLREG]]
+; SI: S_ENDPGM
+define void @shl_2_add_9_i32_2_add_uses(i32 addrspace(1)* %out0, i32 addrspace(1)* %out1, i32 addrspace(1)* %in) #0 {
+  %tid.x = tail call i32 @llvm.r600.read.tidig.x() #1
+  %ptr = getelementptr i32 addrspace(1)* %in, i32 %tid.x
+  %val = load i32 addrspace(1)* %ptr, align 4
+  %add = add i32 %val, 9
+  %result = shl i32 %add, 2
+  store i32 %result, i32 addrspace(1)* %out0, align 4
+  store i32 %add, i32 addrspace(1)* %out1, align 4
+  ret void
+}
+
+; Test with add literal constant
+
+; FUNC-LABEL: @shl_2_add_999_i32
+; SI: V_LSHLREV_B32_e32  [[REG:v[0-9]+]], 2, {{v[0-9]+}}
+; SI: V_ADD_I32_e32 [[RESULT:v[0-9]+]], 0xf9c, [[REG]]
+; SI: BUFFER_STORE_DWORD [[RESULT]]
+; SI: S_ENDPGM
+define void @shl_2_add_999_i32(i32 addrspace(1)* %out, i32 addrspace(1)* %in) #0 {
+  %tid.x = tail call i32 @llvm.r600.read.tidig.x() #1
+  %ptr = getelementptr i32 addrspace(1)* %in, i32 %tid.x
+  %val = load i32 addrspace(1)* %ptr, align 4
+  %shl = add i32 %val, 999
+  %result = shl i32 %shl, 2
+  store i32 %result, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
+; FUNC-LABEL: @test_add_shl_add_constant
+; SI-DAG: S_LOAD_DWORD [[X:s[0-9]+]], s{{\[[0-9]+:[0-9]+\]}}, 0xb
+; SI-DAG: S_LOAD_DWORD [[Y:s[0-9]+]], s{{\[[0-9]+:[0-9]+\]}}, 0xc
+; SI: S_LSHL_B32 [[SHL3:s[0-9]+]], [[X]], 3
+; SI: S_ADD_I32 [[TMP:s[0-9]+]], [[SHL3]], [[Y]]
+; SI: S_ADD_I32 [[RESULT:s[0-9]+]], [[TMP]], 0x3d8
+; SI: V_MOV_B32_e32 [[VRESULT:v[0-9]+]], [[RESULT]]
+; SI: BUFFER_STORE_DWORD [[VRESULT]]
+define void @test_add_shl_add_constant(i32 addrspace(1)* %out, i32 %x, i32 %y) #0 {
+  %add.0 = add i32 %x, 123
+  %shl = shl i32 %add.0, 3
+  %add.1 = add i32 %shl, %y
+   store i32 %add.1, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
+; FUNC-LABEL: @test_add_shl_add_constant_inv
+; SI-DAG: S_LOAD_DWORD [[X:s[0-9]+]], s{{\[[0-9]+:[0-9]+\]}}, 0xb
+; SI-DAG: S_LOAD_DWORD [[Y:s[0-9]+]], s{{\[[0-9]+:[0-9]+\]}}, 0xc
+; SI: S_LSHL_B32 [[SHL3:s[0-9]+]], [[X]], 3
+; SI: S_ADD_I32 [[TMP:s[0-9]+]], [[SHL3]], [[Y]]
+; SI: S_ADD_I32 [[RESULT:s[0-9]+]], [[TMP]], 0x3d8
+; SI: V_MOV_B32_e32 [[VRESULT:v[0-9]+]], [[RESULT]]
+; SI: BUFFER_STORE_DWORD [[VRESULT]]
+
+define void @test_add_shl_add_constant_inv(i32 addrspace(1)* %out, i32 %x, i32 %y) #0 {
+  %add.0 = add i32 %x, 123
+  %shl = shl i32 %add.0, 3
+  %add.1 = add i32 %y, %shl
+  store i32 %add.1, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
+attributes #0 = { nounwind }
+attributes #1 = { nounwind readnone }

diff --git a/test/CodeGen/R600/shl_add_ptr.ll b/test/CodeGen/R600/shl_add_ptr.ll
index b6197c9932c6b9345287a8a57e511c5488f4eae7..ecab1c8bd6024be0dab844f57f9c251d15cd5f39 100644 (file)
--- a/test/CodeGen/R600/shl_add_ptr.ll
+++ b/test/CodeGen/R600/shl_add_ptr.ll
@@ -1,7 +1,4 @@
-; XFAIL: *
-; Enable when patch to perform shl + add constant generic DAG combiner patch is in.
-
-; RUN: llc -march=r600 -mcpu=SI -verify-machineinstrs < %s | FileCheck -check-prefix=SI %s
+; RUN: llc -march=r600 -mcpu=bonaire -verify-machineinstrs < %s | FileCheck -check-prefix=SI %s
 
 ; Test that doing a shift of a pointer with a constant add will be
 ; folded into the constant offset addressing mode even if the add has

diff --git a/test/CodeGen/R600/trunc.ll b/test/CodeGen/R600/trunc.ll
index cee0f4e2b62f2e30cf763a8e90b99567c2a00525..2f4b48236d416d508eb18bfbf9fd119810790264 100644 (file)
--- a/test/CodeGen/R600/trunc.ll
+++ b/test/CodeGen/R600/trunc.ll
@@ -31,10 +31,10 @@ define void @trunc_load_shl_i64(i32 addrspace(1)* %out, i64 %a) {
 
 ; SI-LABEL: @trunc_shl_i64:
 ; SI: S_LOAD_DWORDX2 s{{\[}}[[LO_SREG:[0-9]+]]:{{[0-9]+\]}}, s{{\[[0-9]+:[0-9]+\]}}, 0xd
-; SI: S_ADD_U32 s[[LO_SREG2:[0-9]+]], s[[LO_SREG]],
+; SI: S_LSHL_B64 s{{\[}}[[LO_SHL:[0-9]+]]:{{[0-9]+\]}}, s{{\[}}[[LO_SREG]]:{{[0-9]+\]}}, 2
+; SI: S_ADD_U32 s[[LO_SREG2:[0-9]+]], s[[LO_SHL]],
 ; SI: S_ADDC_U32
-; SI: S_LSHL_B64 s{{\[}}[[LO_SHL:[0-9]+]]:{{[0-9]+\]}}, s{{\[}}[[LO_SREG2]]:{{[0-9]+\]}}, 2
-; SI: V_MOV_B32_e32 v[[LO_VREG:[0-9]+]], s[[LO_SHL]]
+; SI: V_MOV_B32_e32 v[[LO_VREG:[0-9]+]], s[[LO_SREG2]]
 ; SI: BUFFER_STORE_DWORD v[[LO_VREG]],
 define void @trunc_shl_i64(i64 addrspace(1)* %out2, i32 addrspace(1)* %out, i64 %a) {
   %aa = add i64 %a, 234 ; Prevent shrinking store.

diff --git a/test/CodeGen/X86/add_shl_constant.ll b/test/CodeGen/X86/add_shl_constant.ll
new file mode 100644 (file)
index 0000000..2a8e744
--- /dev/null
+++ b/test/CodeGen/X86/add_shl_constant.ll
@@ -0,0 +1,49 @@
+; RUN: llc -march=x86-64 < %s | FileCheck %s
+
+; CHECK-LABEL: add_shl_add_constant_1_i32
+; CHECK: leal 984(%rsi,%rdi,8), %eax
+; CHECK-NEXT: retq
+define i32 @add_shl_add_constant_1_i32(i32 %x, i32 %y) nounwind {
+  %add.0 = add i32 %x, 123
+  %shl = shl i32 %add.0, 3
+  %add.1 = add i32 %shl, %y
+  ret i32 %add.1
+}
+
+; CHECK-LABEL: add_shl_add_constant_2_i32
+; CHECK: leal 984(%rsi,%rdi,8), %eax
+; CHECK-NEXT: retq
+define i32 @add_shl_add_constant_2_i32(i32 %x, i32 %y) nounwind {
+  %add.0 = add i32 %x, 123
+  %shl = shl i32 %add.0, 3
+  %add.1 = add i32 %y, %shl
+  ret i32 %add.1
+}
+
+; CHECK: LCPI2_0:
+; CHECK: .long 984
+; CHECK: _add_shl_add_constant_1_v4i32
+; CHECK: pslld $3, %[[REG:xmm[0-9]+]]
+; CHECK: paddd %xmm1, %[[REG]]
+; CHECK: paddd LCPI2_0(%rip), %[[REG:xmm[0-9]+]]
+; CHECK: retq
+define <4 x i32> @add_shl_add_constant_1_v4i32(<4 x i32> %x, <4 x i32> %y) nounwind {
+  %add.0 = add <4 x i32> %x, <i32 123, i32 123, i32 123, i32 123>
+  %shl = shl <4 x i32> %add.0, <i32 3, i32 3, i32 3, i32 3>
+  %add.1 = add <4 x i32> %shl, %y
+  ret <4 x i32> %add.1
+}
+
+; CHECK: LCPI3_0:
+; CHECK: .long 984
+; CHECK: _add_shl_add_constant_2_v4i32
+; CHECK: pslld $3, %[[REG:xmm[0-9]+]]
+; CHECK: paddd %xmm1, %[[REG]]
+; CHECK: paddd LCPI3_0(%rip), %[[REG:xmm[0-9]+]]
+; CHECK: retq
+define <4 x i32> @add_shl_add_constant_2_v4i32(<4 x i32> %x, <4 x i32> %y) nounwind {
+  %add.0 = add <4 x i32> %x, <i32 123, i32 123, i32 123, i32 123>
+  %shl = shl <4 x i32> %add.0, <i32 3, i32 3, i32 3, i32 3>
+  %add.1 = add <4 x i32> %y, %shl
+  ret <4 x i32> %add.1
+}