[X86] ICMP EQ/NE MIN_SIGNED_INT - avoid immediate argument by using NEG + SETO/SETNO

Fixes #67709

Author: RKSimon

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -23816,6 +23816,18 @@ SDValue X86TargetLowering::emitFlagsForSetcc(SDValue Op0, SDValue Op1,
       }
     }
 
+    // Look for X == INT_MIN or X != INT_MIN. We can use NEG and test for
+    // overflow.
+    if (isMinSignedConstant(Op1)) {
+      EVT VT = Op0.getValueType();
+      SDVTList CmpVTs = DAG.getVTList(VT, MVT::i32);
+      X86::CondCode CondCode = CC == ISD::SETEQ ? X86::COND_O : X86::COND_NO;
+      X86CC = DAG.getTargetConstant(CondCode, dl, MVT::i8);
+      SDValue Neg =
+          DAG.getNode(X86ISD::SUB, dl, CmpVTs, DAG.getConstant(0, dl, VT), Op0);
+      return SDValue(Neg.getNode(), 1);
+    }
+
     // Try to use the carry flag from the add in place of an separate CMP for:
     // (seteq (add X, -1), -1). Similar for setne.
     if (isAllOnesConstant(Op1) && Op0.getOpcode() == ISD::ADD &&

llvm/test/CodeGen/X86/2008-06-16-SubregsBug.ll

@@ -8,8 +8,8 @@ define i16 @test(ptr %tmp179) nounwind  {
 ; CHECK-NEXT:    movzwl (%eax), %eax
 ; CHECK-NEXT:    movl %eax, %ecx
 ; CHECK-NEXT:    andl $64512, %ecx ## imm = 0xFC00
-; CHECK-NEXT:    cmpl $32768, %ecx ## imm = 0x8000
-; CHECK-NEXT:    jne LBB0_2
+; CHECK-NEXT:    negw %cx
+; CHECK-NEXT:    jno LBB0_2
 ; CHECK-NEXT:  ## %bb.1: ## %bb189
 ; CHECK-NEXT:    ## kill: def $ax killed $ax killed $eax
 ; CHECK-NEXT:    retl

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

@@ -58,8 +58,8 @@ define i32 @combine_sdiv_by_minsigned(i32 %x) {
 ; CHECK-LABEL: combine_sdiv_by_minsigned:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    xorl %eax, %eax
-; CHECK-NEXT:    cmpl $-2147483648, %edi # imm = 0x80000000
-; CHECK-NEXT:    sete %al
+; CHECK-NEXT:    negl %edi
+; CHECK-NEXT:    seto %al
 ; CHECK-NEXT:    retq
   %1 = sdiv i32 %x, -2147483648
   ret i32 %1

llvm/test/CodeGen/X86/is_fpclass.ll

@@ -936,15 +936,16 @@ entry:
 define i1 @is_minus_zero_f(float %x) {
 ; CHECK-32-LABEL: is_minus_zero_f:
 ; CHECK-32:       # %bb.0: # %entry
-; CHECK-32-NEXT:    cmpl $-2147483648, {{[0-9]+}}(%esp) # imm = 0x80000000
-; CHECK-32-NEXT:    sete %al
+; CHECK-32-NEXT:    xorl %eax, %eax
+; CHECK-32-NEXT:    cmpl {{[0-9]+}}(%esp), %eax
+; CHECK-32-NEXT:    seto %al
 ; CHECK-32-NEXT:    retl
 ;
 ; CHECK-64-LABEL: is_minus_zero_f:
 ; CHECK-64:       # %bb.0: # %entry
 ; CHECK-64-NEXT:    movd %xmm0, %eax
-; CHECK-64-NEXT:    cmpl $-2147483648, %eax # imm = 0x80000000
-; CHECK-64-NEXT:    sete %al
+; CHECK-64-NEXT:    negl %eax
+; CHECK-64-NEXT:    seto %al
 ; CHECK-64-NEXT:    retq
 entry:
   %0 = tail call i1 @llvm.is.fpclass.f32(float %x, i32 32)  ; 0x20 = "-zero"
@@ -954,15 +955,16 @@ entry:
 define i1 @not_is_minus_zero_f(float %x) {
 ; CHECK-32-LABEL: not_is_minus_zero_f:
 ; CHECK-32:       # %bb.0: # %entry
-; CHECK-32-NEXT:    cmpl $-2147483648, {{[0-9]+}}(%esp) # imm = 0x80000000
-; CHECK-32-NEXT:    setne %al
+; CHECK-32-NEXT:    xorl %eax, %eax
+; CHECK-32-NEXT:    cmpl {{[0-9]+}}(%esp), %eax
+; CHECK-32-NEXT:    setno %al
 ; CHECK-32-NEXT:    retl
 ;
 ; CHECK-64-LABEL: not_is_minus_zero_f:
 ; CHECK-64:       # %bb.0: # %entry
 ; CHECK-64-NEXT:    movd %xmm0, %eax
-; CHECK-64-NEXT:    cmpl $-2147483648, %eax # imm = 0x80000000
-; CHECK-64-NEXT:    setne %al
+; CHECK-64-NEXT:    negl %eax
+; CHECK-64-NEXT:    setno %al
 ; CHECK-64-NEXT:    retq
 entry:
   %0 = tail call i1 @llvm.is.fpclass.f32(float %x, i32 991)  ; ~0x20 = ~"-zero"

llvm/test/CodeGen/X86/lsr-overflow.ll

@@ -4,9 +4,9 @@
 ; The comparison uses the pre-inc value, which could lead LSR to
 ; try to compute -INT64_MIN.
 
-; CHECK: movabsq $-9223372036854775808, %rax
-; CHECK: cmpq  %rax,
-; CHECK: sete  %al
+; CHECK-NOT: movabsq $-9223372036854775808, %rax
+; CHECK: negq  %r
+; CHECK-NEXT: seto  %al
 
 declare i64 @bar()
 

llvm/test/CodeGen/X86/shrink-compare-pgso.ll

@@ -265,8 +265,8 @@ if.end:
 define dso_local void @test_sext_i8_icmp_neg128(i8 %x) nounwind !prof !14 {
 ; CHECK-LABEL: test_sext_i8_icmp_neg128:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    cmpb $-128, %dil
-; CHECK-NEXT:    je bar # TAILCALL
+; CHECK-NEXT:    negb %dil
+; CHECK-NEXT:    jo bar # TAILCALL
 ; CHECK-NEXT:  # %bb.1: # %if.end
 ; CHECK-NEXT:    retq
 entry:

llvm/test/CodeGen/X86/shrink-compare.ll

@@ -265,8 +265,8 @@ if.end:
 define dso_local void @test_sext_i8_icmp_neg128(i8 %x) nounwind minsize {
 ; CHECK-LABEL: test_sext_i8_icmp_neg128:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    cmpb $-128, %dil
-; CHECK-NEXT:    je bar # TAILCALL
+; CHECK-NEXT:    negb %dil
+; CHECK-NEXT:    jo bar # TAILCALL
 ; CHECK-NEXT:  # %bb.1: # %if.end
 ; CHECK-NEXT:    retq
 entry: