[X86] Fold generic ADD/SUB with constants to X86ISD::SUB/ADD

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -57617,10 +57617,10 @@ static SDValue combineX86AddSub(SDNode *N, SelectionDAG &DAG,
   }
 
   // Fold any similar generic ADD/SUB opcodes to reuse this node.
-  auto MatchGeneric = [&](SDValue N0, SDValue N1, bool Negate) {
+  auto MatchGeneric = [&](unsigned Opc, SDValue N0, SDValue N1, bool Negate) {
     SDValue Ops[] = {N0, N1};
     SDVTList VTs = DAG.getVTList(N->getValueType(0));
-    if (SDNode *GenericAddSub = DAG.getNodeIfExists(GenericOpc, VTs, Ops)) {
+    if (SDNode *GenericAddSub = DAG.getNodeIfExists(Opc, VTs, Ops)) {
       SDValue Op(N, 0);
       if (Negate) {
         // Bail if this is only used by a user of the x86 add/sub.
@@ -57632,8 +57632,25 @@ static SDValue combineX86AddSub(SDNode *N, SelectionDAG &DAG,
       DCI.CombineTo(GenericAddSub, Op);
     }
   };
-  MatchGeneric(LHS, RHS, false);
-  MatchGeneric(RHS, LHS, X86ISD::SUB == N->getOpcode());
+  MatchGeneric(GenericOpc, LHS, RHS, false);
+  MatchGeneric(GenericOpc, RHS, LHS, X86ISD::SUB == N->getOpcode());
+
+  if (auto *Const = dyn_cast<ConstantSDNode>(RHS)) {
+    SDValue NegC = DAG.getConstant(-Const->getAPIntValue(), DL, VT);
+    if (X86ISD::SUB == N->getOpcode()) {
+      // Fold generic add(LHS, -C) to X86ISD::SUB(LHS, C).
+      MatchGeneric(ISD::ADD, LHS, NegC, false);
+    } else {
+      // Negate X86ISD::ADD(LHS, C) and replace generic sub(-C, LHS).
+      MatchGeneric(ISD::SUB, NegC, LHS, true);
+    }
+  } else if (auto *Const = dyn_cast<ConstantSDNode>(LHS)) {
+    if (X86ISD::SUB == N->getOpcode()) {
+      SDValue NegC = DAG.getConstant(-Const->getAPIntValue(), DL, VT);
+      // Negate X86ISD::SUB(C, RHS) and replace generic add(RHS, -C).
+      MatchGeneric(ISD::ADD, RHS, NegC, true);
+    }
+  }
 
   // TODO: Can we drop the ZeroSecondOpOnly limit? This is to guarantee that the
   // EFLAGS result doesn't change.

llvm/test/CodeGen/X86/combine-adc.ll

@@ -89,4 +89,52 @@ define i32 @adc_merge_constants(i32 %a0) nounwind {
   ret i32 %sum
 }
 
+define i32 @adc_merge_sub(i32 %a0) nounwind {
+; X86-LABEL: adc_merge_sub:
+; X86:       # %bb.0:
+; X86-NEXT:    pushl %edi
+; X86-NEXT:    pushl %esi
+; X86-NEXT:    movl {{[0-9]+}}(%esp), %edi
+; X86-NEXT:    xorl %eax, %eax
+; X86-NEXT:    addl $42, %edi
+; X86-NEXT:    setb %al
+; X86-NEXT:    movl %edi, %esi
+; X86-NEXT:    negl %esi
+; X86-NEXT:    pushl %eax
+; X86-NEXT:    calll use@PLT
+; X86-NEXT:    addl $4, %esp
+; X86-NEXT:    xorl %edi, %esi
+; X86-NEXT:    movl %esi, %eax
+; X86-NEXT:    popl %esi
+; X86-NEXT:    popl %edi
+; X86-NEXT:    retl
+;
+; X64-LABEL: adc_merge_sub:
+; X64:       # %bb.0:
+; X64-NEXT:    pushq %rbp
+; X64-NEXT:    pushq %rbx
+; X64-NEXT:    pushq %rax
+; X64-NEXT:    movl %edi, %ebx
+; X64-NEXT:    xorl %edi, %edi
+; X64-NEXT:    addl $42, %ebx
+; X64-NEXT:    setb %dil
+; X64-NEXT:    movl %ebx, %ebp
+; X64-NEXT:    negl %ebp
+; X64-NEXT:    callq use@PLT
+; X64-NEXT:    xorl %ebx, %ebp
+; X64-NEXT:    movl %ebp, %eax
+; X64-NEXT:    addq $8, %rsp
+; X64-NEXT:    popq %rbx
+; X64-NEXT:    popq %rbp
+; X64-NEXT:    retq
+  %adc = tail call { i8, i32 } @llvm.x86.addcarry.32(i8 0, i32 %a0, i32 42)
+  %carry = extractvalue { i8, i32 } %adc, 0
+  call void @use(i8 %carry)
+  %sum = extractvalue { i8, i32 } %adc, 1
+  %sub = sub i32 -42, %a0
+  %result = xor i32 %sum, %sub
+  ret i32 %result
+}
+
 declare { i8, i32 } @llvm.x86.addcarry.32(i8, i32, i32)
+declare void @use(i8)

llvm/test/CodeGen/X86/combine-sbb.ll

@@ -333,4 +333,85 @@ define i32 @PR40483_sub6(ptr, i32) nounwind {
   ret i32 %10
 }
 
+define i32 @sbb_merge_add1(i32 %a0) nounwind {
+; X86-LABEL: sbb_merge_add1:
+; X86:       # %bb.0:
+; X86-NEXT:    xorl %eax, %eax
+; X86-NEXT:    cmpl $42, {{[0-9]+}}(%esp)
+; X86-NEXT:    setb %al
+; X86-NEXT:    pushl %eax
+; X86-NEXT:    calll use@PLT
+; X86-NEXT:    addl $4, %esp
+; X86-NEXT:    xorl %eax, %eax
+; X86-NEXT:    retl
+;
+; X64-LABEL: sbb_merge_add1:
+; X64:       # %bb.0:
+; X64-NEXT:    pushq %rax
+; X64-NEXT:    xorl %eax, %eax
+; X64-NEXT:    cmpl $42, %edi
+; X64-NEXT:    setb %al
+; X64-NEXT:    movl %eax, %edi
+; X64-NEXT:    callq use@PLT
+; X64-NEXT:    xorl %eax, %eax
+; X64-NEXT:    popq %rcx
+; X64-NEXT:    retq
+  %sbb = tail call { i8, i32 } @llvm.x86.subborrow.32(i8 0, i32 %a0, i32 42)
+  %borrow = extractvalue { i8, i32 } %sbb, 0
+  call void @use(i8 %borrow)
+  %diff = extractvalue { i8, i32 } %sbb, 1
+  %add = add i32 %a0, -42
+  %result = xor i32 %diff, %add
+  ret i32 %result
+}
+
+define i32 @sbb_merge_add2(i32 %a0) nounwind {
+; X86-LABEL: sbb_merge_add2:
+; X86:       # %bb.0:
+; X86-NEXT:    pushl %edi
+; X86-NEXT:    pushl %esi
+; X86-NEXT:    movl $42, %edi
+; X86-NEXT:    xorl %eax, %eax
+; X86-NEXT:    subl {{[0-9]+}}(%esp), %edi
+; X86-NEXT:    setb %al
+; X86-NEXT:    movl %edi, %esi
+; X86-NEXT:    negl %esi
+; X86-NEXT:    pushl %eax
+; X86-NEXT:    calll use@PLT
+; X86-NEXT:    addl $4, %esp
+; X86-NEXT:    xorl %edi, %esi
+; X86-NEXT:    movl %esi, %eax
+; X86-NEXT:    popl %esi
+; X86-NEXT:    popl %edi
+; X86-NEXT:    retl
+;
+; X64-LABEL: sbb_merge_add2:
+; X64:       # %bb.0:
+; X64-NEXT:    pushq %rbp
+; X64-NEXT:    pushq %rbx
+; X64-NEXT:    pushq %rax
+; X64-NEXT:    movl $42, %ebp
+; X64-NEXT:    xorl %eax, %eax
+; X64-NEXT:    subl %edi, %ebp
+; X64-NEXT:    setb %al
+; X64-NEXT:    movl %ebp, %ebx
+; X64-NEXT:    negl %ebx
+; X64-NEXT:    movl %eax, %edi
+; X64-NEXT:    callq use@PLT
+; X64-NEXT:    xorl %ebp, %ebx
+; X64-NEXT:    movl %ebx, %eax
+; X64-NEXT:    addq $8, %rsp
+; X64-NEXT:    popq %rbx
+; X64-NEXT:    popq %rbp
+; X64-NEXT:    retq
+  %sbb = tail call { i8, i32 } @llvm.x86.subborrow.32(i8 0, i32 42, i32 %a0)
+  %borrow = extractvalue { i8, i32 } %sbb, 0
+  call void @use(i8 %borrow)
+  %diff = extractvalue { i8, i32 } %sbb, 1
+  %add = add i32 %a0, -42
+  %result = xor i32 %diff, %add
+  ret i32 %result
+}
+
 declare { i8, i32 } @llvm.x86.subborrow.32(i8, i32, i32)
+declare void @use(i8)

llvm/test/CodeGen/X86/dag-update-nodetomatch.ll

@@ -96,6 +96,17 @@ entry:
 define void @_Z2x6v() local_unnamed_addr {
 ; CHECK-LABEL: _Z2x6v:
 ; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movq x1@GOTPCREL(%rip), %rax
+; CHECK-NEXT:    movl (%rax), %edx
+; CHECK-NEXT:    andl $511, %edx # imm = 0x1FF
+; CHECK-NEXT:    leaq 1(%rdx), %rax
+; CHECK-NEXT:    movq x4@GOTPCREL(%rip), %rcx
+; CHECK-NEXT:    movl %eax, (%rcx)
+; CHECK-NEXT:    movq x3@GOTPCREL(%rip), %rcx
+; CHECK-NEXT:    movl (%rcx), %ecx
+; CHECK-NEXT:    testl %ecx, %ecx
+; CHECK-NEXT:    je .LBB1_18
+; CHECK-NEXT:  # %bb.1: # %for.cond1thread-pre-split.lr.ph
 ; CHECK-NEXT:    pushq %rbp
 ; CHECK-NEXT:    .cfi_def_cfa_offset 16
 ; CHECK-NEXT:    pushq %r15
@@ -114,58 +125,47 @@ define void @_Z2x6v() local_unnamed_addr {
 ; CHECK-NEXT:    .cfi_offset %r14, -32
 ; CHECK-NEXT:    .cfi_offset %r15, -24
 ; CHECK-NEXT:    .cfi_offset %rbp, -16
-; CHECK-NEXT:    movq x1@GOTPCREL(%rip), %rax
-; CHECK-NEXT:    movl (%rax), %ebx
-; CHECK-NEXT:    andl $511, %ebx # imm = 0x1FF
-; CHECK-NEXT:    leaq 1(%rbx), %rax
-; CHECK-NEXT:    movq x4@GOTPCREL(%rip), %rcx
-; CHECK-NEXT:    movl %eax, (%rcx)
-; CHECK-NEXT:    movq x3@GOTPCREL(%rip), %rcx
-; CHECK-NEXT:    movl (%rcx), %ecx
-; CHECK-NEXT:    testl %ecx, %ecx
-; CHECK-NEXT:    je .LBB1_18
-; CHECK-NEXT:  # %bb.1: # %for.cond1thread-pre-split.lr.ph
-; CHECK-NEXT:    movq x5@GOTPCREL(%rip), %rdx
-; CHECK-NEXT:    movq (%rdx), %rsi
-; CHECK-NEXT:    movl %ecx, %edx
-; CHECK-NEXT:    notl %edx
-; CHECK-NEXT:    leaq 8(,%rdx,8), %rdi
+; CHECK-NEXT:    movq x5@GOTPCREL(%rip), %rsi
+; CHECK-NEXT:    movq (%rsi), %rsi
+; CHECK-NEXT:    movl %ecx, %edi
+; CHECK-NEXT:    notl %edi
+; CHECK-NEXT:    leaq 8(,%rdi,8), %rdi
 ; CHECK-NEXT:    imulq %rax, %rdi
 ; CHECK-NEXT:    addq %rsi, %rdi
 ; CHECK-NEXT:    movq x2@GOTPCREL(%rip), %r8
-; CHECK-NEXT:    movl (%r8), %edx
-; CHECK-NEXT:    leal 8(,%rbx,8), %eax
+; CHECK-NEXT:    movl (%r8), %r9d
+; CHECK-NEXT:    leal 8(,%rdx,8), %eax
 ; CHECK-NEXT:    movq %rax, {{[-0-9]+}}(%r{{[sb]}}p) # 8-byte Spill
-; CHECK-NEXT:    leaq 32(%rsi), %r11
-; CHECK-NEXT:    leaq 8(,%rbx,8), %rbx
-; CHECK-NEXT:    xorl %r14d, %r14d
-; CHECK-NEXT:    movq x0@GOTPCREL(%rip), %r15
-; CHECK-NEXT:    movq %rsi, %r12
+; CHECK-NEXT:    leaq 32(%rsi), %rbx
+; CHECK-NEXT:    leaq 8(,%rdx,8), %r14
+; CHECK-NEXT:    xorl %r15d, %r15d
+; CHECK-NEXT:    movq x0@GOTPCREL(%rip), %r12
+; CHECK-NEXT:    movq %rsi, %r13
 ; CHECK-NEXT:    jmp .LBB1_2
 ; CHECK-NEXT:    .p2align 4
 ; CHECK-NEXT:  .LBB1_15: # %for.cond1.for.inc3_crit_edge
 ; CHECK-NEXT:    # in Loop: Header=BB1_2 Depth=1
-; CHECK-NEXT:    movl %edx, (%r8)
+; CHECK-NEXT:    movl %r9d, (%r8)
 ; CHECK-NEXT:  .LBB1_16: # %for.inc3
 ; CHECK-NEXT:    # in Loop: Header=BB1_2 Depth=1
-; CHECK-NEXT:    addq %rbx, %r12
-; CHECK-NEXT:    incq %r14
-; CHECK-NEXT:    addq %rbx, %r11
+; CHECK-NEXT:    addq %r14, %r13
+; CHECK-NEXT:    incq %r15
+; CHECK-NEXT:    addq %r14, %rbx
 ; CHECK-NEXT:    incl %ecx
 ; CHECK-NEXT:    je .LBB1_17
 ; CHECK-NEXT:  .LBB1_2: # %for.cond1thread-pre-split
 ; CHECK-NEXT:    # =>This Loop Header: Depth=1
 ; CHECK-NEXT:    # Child Loop BB1_12 Depth 2
 ; CHECK-NEXT:    # Child Loop BB1_14 Depth 2
-; CHECK-NEXT:    testl %edx, %edx
+; CHECK-NEXT:    testl %r9d, %r9d
 ; CHECK-NEXT:    jns .LBB1_16
 ; CHECK-NEXT:  # %bb.3: # %for.body2.preheader
 ; CHECK-NEXT:    # in Loop: Header=BB1_2 Depth=1
-; CHECK-NEXT:    movslq %edx, %r13
-; CHECK-NEXT:    testq %r13, %r13
+; CHECK-NEXT:    movslq %r9d, %r9
+; CHECK-NEXT:    testq %r9, %r9
 ; CHECK-NEXT:    movq $-1, %rbp
-; CHECK-NEXT:    cmovnsq %r13, %rbp
-; CHECK-NEXT:    subq %r13, %rbp
+; CHECK-NEXT:    cmovnsq %r9, %rbp
+; CHECK-NEXT:    subq %r9, %rbp
 ; CHECK-NEXT:    incq %rbp
 ; CHECK-NEXT:    cmpq $4, %rbp
 ; CHECK-NEXT:    jb .LBB1_14
@@ -177,20 +177,20 @@ define void @_Z2x6v() local_unnamed_addr {
 ; CHECK-NEXT:  # %bb.5: # %vector.memcheck
 ; CHECK-NEXT:    # in Loop: Header=BB1_2 Depth=1
 ; CHECK-NEXT:    movq {{[-0-9]+}}(%r{{[sb]}}p), %rax # 8-byte Reload
-; CHECK-NEXT:    imulq %r14, %rax
-; CHECK-NEXT:    leaq (%rsi,%rax), %r10
-; CHECK-NEXT:    leaq (%r10,%r13,8), %r9
-; CHECK-NEXT:    testq %r13, %r13
-; CHECK-NEXT:    movq $-1, %r10
-; CHECK-NEXT:    cmovnsq %r13, %r10
-; CHECK-NEXT:    cmpq %r15, %r9
+; CHECK-NEXT:    imulq %r15, %rax
+; CHECK-NEXT:    leaq (%rsi,%rax), %r11
+; CHECK-NEXT:    leaq (%r11,%r9,8), %r10
+; CHECK-NEXT:    testq %r9, %r9
+; CHECK-NEXT:    movq $-1, %r11
+; CHECK-NEXT:    cmovnsq %r9, %r11
+; CHECK-NEXT:    cmpq %r12, %r10
 ; CHECK-NEXT:    jae .LBB1_7
 ; CHECK-NEXT:  # %bb.6: # %vector.memcheck
 ; CHECK-NEXT:    # in Loop: Header=BB1_2 Depth=1
-; CHECK-NEXT:    leaq 8(%rsi), %r9
-; CHECK-NEXT:    addq %r9, %rax
-; CHECK-NEXT:    leaq (%rax,%r10,8), %rax
-; CHECK-NEXT:    cmpq %r15, %rax
+; CHECK-NEXT:    leaq 8(%rsi), %r10
+; CHECK-NEXT:    addq %r10, %rax
+; CHECK-NEXT:    leaq (%rax,%r11,8), %rax
+; CHECK-NEXT:    cmpq %r12, %rax
 ; CHECK-NEXT:    ja .LBB1_14
 ; CHECK-NEXT:  .LBB1_7: # %vector.body.preheader
 ; CHECK-NEXT:    # in Loop: Header=BB1_2 Depth=1
@@ -201,58 +201,54 @@ define void @_Z2x6v() local_unnamed_addr {
 ; CHECK-NEXT:    # in Loop: Header=BB1_2 Depth=1
 ; CHECK-NEXT:    movq {{.*#+}} xmm0 = mem[0],zero
 ; CHECK-NEXT:    pshufd {{.*#+}} xmm0 = xmm0[0,1,0,1]
-; CHECK-NEXT:    movdqu %xmm0, (%r12,%r13,8)
-; CHECK-NEXT:    movdqu %xmm0, 16(%r12,%r13,8)
-; CHECK-NEXT:    movl $4, %r10d
+; CHECK-NEXT:    movdqu %xmm0, (%r13,%r9,8)
+; CHECK-NEXT:    movdqu %xmm0, 16(%r13,%r9,8)
+; CHECK-NEXT:    movl $4, %r11d
 ; CHECK-NEXT:    shrq $2, %rax
 ; CHECK-NEXT:    jne .LBB1_11
 ; CHECK-NEXT:    jmp .LBB1_13
 ; CHECK-NEXT:  .LBB1_8: # in Loop: Header=BB1_2 Depth=1
-; CHECK-NEXT:    xorl %r10d, %r10d
+; CHECK-NEXT:    xorl %r11d, %r11d
 ; CHECK-NEXT:    shrq $2, %rax
 ; CHECK-NEXT:    je .LBB1_13
 ; CHECK-NEXT:  .LBB1_11: # %vector.body.preheader.new
 ; CHECK-NEXT:    # in Loop: Header=BB1_2 Depth=1
 ; CHECK-NEXT:    movq {{.*#+}} xmm0 = mem[0],zero
 ; CHECK-NEXT:    pshufd {{.*#+}} xmm0 = xmm0[0,1,0,1]
-; CHECK-NEXT:    movq %r10, %rax
+; CHECK-NEXT:    movq %r11, %rax
 ; CHECK-NEXT:    subq %rdx, %rax
-; CHECK-NEXT:    addq %r13, %r10
-; CHECK-NEXT:    leaq (%r11,%r10,8), %r10
+; CHECK-NEXT:    addq %r9, %r11
+; CHECK-NEXT:    leaq (%rbx,%r11,8), %r11
 ; CHECK-NEXT:    .p2align 4
 ; CHECK-NEXT:  .LBB1_12: # %vector.body
 ; CHECK-NEXT:    # Parent Loop BB1_2 Depth=1
 ; CHECK-NEXT:    # => This Inner Loop Header: Depth=2
-; CHECK-NEXT:    movdqu %xmm0, -32(%r10)
-; CHECK-NEXT:    movdqu %xmm0, -16(%r10)
-; CHECK-NEXT:    movdqu %xmm0, (%r10)
-; CHECK-NEXT:    movdqu %xmm0, 16(%r10)
-; CHECK-NEXT:    addq $64, %r10
+; CHECK-NEXT:    movdqu %xmm0, -32(%r11)
+; CHECK-NEXT:    movdqu %xmm0, -16(%r11)
+; CHECK-NEXT:    movdqu %xmm0, (%r11)
+; CHECK-NEXT:    movdqu %xmm0, 16(%r11)
+; CHECK-NEXT:    addq $64, %r11
 ; CHECK-NEXT:    addq $8, %rax
 ; CHECK-NEXT:    jne .LBB1_12
 ; CHECK-NEXT:  .LBB1_13: # %middle.block
 ; CHECK-NEXT:    # in Loop: Header=BB1_2 Depth=1
-; CHECK-NEXT:    addq %rdx, %r13
+; CHECK-NEXT:    addq %rdx, %r9
 ; CHECK-NEXT:    cmpq %rdx, %rbp
-; CHECK-NEXT:    movq %r13, %rdx
 ; CHECK-NEXT:    je .LBB1_15
 ; CHECK-NEXT:    .p2align 4
 ; CHECK-NEXT:  .LBB1_14: # %for.body2
 ; CHECK-NEXT:    # Parent Loop BB1_2 Depth=1
 ; CHECK-NEXT:    # => This Inner Loop Header: Depth=2
-; CHECK-NEXT:    movq (%r15), %rax
-; CHECK-NEXT:    movq %rax, (%r12,%r13,8)
-; CHECK-NEXT:    leaq 1(%r13), %rdx
-; CHECK-NEXT:    cmpq $-1, %r13
-; CHECK-NEXT:    movq %rdx, %r13
+; CHECK-NEXT:    movq (%r12), %rax
+; CHECK-NEXT:    movq %rax, (%r13,%r9,8)
+; CHECK-NEXT:    incq %r9
 ; CHECK-NEXT:    jl .LBB1_14
 ; CHECK-NEXT:    jmp .LBB1_15
 ; CHECK-NEXT:  .LBB1_17: # %for.cond.for.end5_crit_edge
 ; CHECK-NEXT:    movq x5@GOTPCREL(%rip), %rax
 ; CHECK-NEXT:    movq %rdi, (%rax)
 ; CHECK-NEXT:    movq x3@GOTPCREL(%rip), %rax
 ; CHECK-NEXT:    movl $0, (%rax)
-; CHECK-NEXT:  .LBB1_18: # %for.end5
 ; CHECK-NEXT:    popq %rbx
 ; CHECK-NEXT:    .cfi_def_cfa_offset 48
 ; CHECK-NEXT:    popq %r12
@@ -265,6 +261,13 @@ define void @_Z2x6v() local_unnamed_addr {
 ; CHECK-NEXT:    .cfi_def_cfa_offset 16
 ; CHECK-NEXT:    popq %rbp
 ; CHECK-NEXT:    .cfi_def_cfa_offset 8
+; CHECK-NEXT:    .cfi_restore %rbx
+; CHECK-NEXT:    .cfi_restore %r12
+; CHECK-NEXT:    .cfi_restore %r13
+; CHECK-NEXT:    .cfi_restore %r14
+; CHECK-NEXT:    .cfi_restore %r15
+; CHECK-NEXT:    .cfi_restore %rbp
+; CHECK-NEXT:  .LBB1_18: # %for.end5
 ; CHECK-NEXT:    retq
 entry:
   %0 = load i32, ptr @x1, align 4