diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 8eadf079d4f2f..de26ce2853c5b 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -46433,6 +46433,62 @@ static SDValue combineSetCCAtomicArith(SDValue Cmp, X86::CondCode &CC,
   return LockOp;
 }
 
+// Check whether we're just testing the signbit, and whether we can simplify
+// this by tracking where the signbit came from.
+static SDValue checkSignTestSetCCCombine(SDValue Cmp, X86::CondCode &CC,
+                                         SelectionDAG &DAG) {
+  if (CC != X86::COND_S && CC != X86::COND_NS)
+    return SDValue();
+
+  if (!Cmp.hasOneUse())
+    return SDValue();
+
+  SDValue Src;
+  if (Cmp.getOpcode() == X86ISD::CMP) {
+    // CMP(X,0) -> signbit test
+    if (!isNullConstant(Cmp.getOperand(1)))
+      return SDValue();
+    Src = Cmp.getOperand(0);
+    // Peek through a SRA node as we just need the signbit.
+    // TODO: Remove one use limit once sdiv-fix regressions are fixed.
+    // TODO: Use SimplifyDemandedBits instead of just SRA?
+    if (Src.getOpcode() != ISD::SRA || !Src.hasOneUse())
+      return SDValue();
+    Src = Src.getOperand(0);
+  } else if (Cmp.getOpcode() == X86ISD::OR) {
+    // OR(X,Y) -> see if only one operand contributes to the signbit.
+    // TODO: XOR(X,Y) -> see if only one operand contributes to the signbit.
+    if (DAG.SignBitIsZero(Cmp.getOperand(0)))
+      Src = Cmp.getOperand(1);
+    else if (DAG.SignBitIsZero(Cmp.getOperand(1)))
+      Src = Cmp.getOperand(0);
+    else
+      return SDValue();
+  } else {
+    return SDValue();
+  }
+
+  // Replace with a TEST on the MSB.
+  SDLoc DL(Cmp);
+  MVT SrcVT = Src.getSimpleValueType();
+  APInt BitMask = APInt::getSignMask(SrcVT.getScalarSizeInBits());
+
+  // If Src came from a SHL (probably from an expanded SIGN_EXTEND_INREG), then
+  // peek through and adjust the TEST bit.
+  if (Src.getOpcode() == ISD::SHL) {
+    if (std::optional<uint64_t> ShiftAmt = DAG.getValidShiftAmount(Src)) {
+      Src = Src.getOperand(0);
+      BitMask.lshrInPlace(*ShiftAmt);
+    }
+  }
+
+  SDValue Mask = DAG.getNode(ISD::AND, DL, SrcVT, Src,
+                             DAG.getConstant(BitMask, DL, SrcVT));
+  CC = CC == X86::COND_S ? X86::COND_NE : X86::COND_E;
+  return DAG.getNode(X86ISD::CMP, DL, MVT::i32, Mask,
+                     DAG.getConstant(0, DL, SrcVT));
+}
+
 // Check whether a boolean test is testing a boolean value generated by
 // X86ISD::SETCC. If so, return the operand of that SETCC and proper condition
 // code.
@@ -47072,6 +47128,9 @@ static SDValue combineSetCCEFLAGS(SDValue EFLAGS, X86::CondCode &CC,
     if (SDValue Flags = combineCarryThroughADD(EFLAGS, DAG))
       return Flags;
 
+  if (SDValue R = checkSignTestSetCCCombine(EFLAGS, CC, DAG))
+    return R;
+
   if (SDValue R = checkBoolTestSetCCCombine(EFLAGS, CC))
     return R;
 
diff --git a/llvm/test/CodeGen/X86/is_fpclass-fp80.ll b/llvm/test/CodeGen/X86/is_fpclass-fp80.ll
index ec2323ac2250c..7d0c5838c1554 100644
--- a/llvm/test/CodeGen/X86/is_fpclass-fp80.ll
+++ b/llvm/test/CodeGen/X86/is_fpclass-fp80.ll
@@ -363,10 +363,9 @@ define i1 @is_posnormal_f80(x86_fp80 %x) {
 ; CHECK-32-NEXT:    pushl %esi
 ; CHECK-32-NEXT:    .cfi_def_cfa_offset 8
 ; CHECK-32-NEXT:    .cfi_offset %esi, -8
-; CHECK-32-NEXT:    movzwl {{[0-9]+}}(%esp), %edx
-; CHECK-32-NEXT:    movswl %dx, %ecx
-; CHECK-32-NEXT:    sarl $15, %ecx
 ; CHECK-32-NEXT:    movl {{[0-9]+}}(%esp), %eax
+; CHECK-32-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
+; CHECK-32-NEXT:    movl %ecx, %edx
 ; CHECK-32-NEXT:    andl $32767, %edx # imm = 0x7FFF
 ; CHECK-32-NEXT:    decl %edx
 ; CHECK-32-NEXT:    movzwl %dx, %edx
@@ -374,8 +373,8 @@ define i1 @is_posnormal_f80(x86_fp80 %x) {
 ; CHECK-32-NEXT:    cmpl $32766, %edx # imm = 0x7FFE
 ; CHECK-32-NEXT:    sbbl %esi, %esi
 ; CHECK-32-NEXT:    setb %dl
-; CHECK-32-NEXT:    testl %ecx, %ecx
-; CHECK-32-NEXT:    setns %cl
+; CHECK-32-NEXT:    testl $32768, %ecx # imm = 0x8000
+; CHECK-32-NEXT:    sete %cl
 ; CHECK-32-NEXT:    shrl $31, %eax
 ; CHECK-32-NEXT:    andb %cl, %al
 ; CHECK-32-NEXT:    andb %dl, %al
@@ -411,10 +410,9 @@ define i1 @is_negnormal_f80(x86_fp80 %x) {
 ; CHECK-32-NEXT:    pushl %esi
 ; CHECK-32-NEXT:    .cfi_def_cfa_offset 8
 ; CHECK-32-NEXT:    .cfi_offset %esi, -8
-; CHECK-32-NEXT:    movzwl {{[0-9]+}}(%esp), %edx
-; CHECK-32-NEXT:    movswl %dx, %ecx
-; CHECK-32-NEXT:    sarl $15, %ecx
 ; CHECK-32-NEXT:    movl {{[0-9]+}}(%esp), %eax
+; CHECK-32-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
+; CHECK-32-NEXT:    movl %ecx, %edx
 ; CHECK-32-NEXT:    andl $32767, %edx # imm = 0x7FFF
 ; CHECK-32-NEXT:    decl %edx
 ; CHECK-32-NEXT:    movzwl %dx, %edx
@@ -422,8 +420,8 @@ define i1 @is_negnormal_f80(x86_fp80 %x) {
 ; CHECK-32-NEXT:    cmpl $32766, %edx # imm = 0x7FFE
 ; CHECK-32-NEXT:    sbbl %esi, %esi
 ; CHECK-32-NEXT:    setb %dl
-; CHECK-32-NEXT:    testl %ecx, %ecx
-; CHECK-32-NEXT:    sets %cl
+; CHECK-32-NEXT:    testl $32768, %ecx # imm = 0x8000
+; CHECK-32-NEXT:    setne %cl
 ; CHECK-32-NEXT:    shrl $31, %eax
 ; CHECK-32-NEXT:    andb %cl, %al
 ; CHECK-32-NEXT:    andb %dl, %al
@@ -543,24 +541,23 @@ define i1 @is_negsubnormal_f80(x86_fp80 %x) {
 ; CHECK-32-NEXT:    .cfi_def_cfa_offset 12
 ; CHECK-32-NEXT:    .cfi_offset %esi, -12
 ; CHECK-32-NEXT:    .cfi_offset %edi, -8
-; CHECK-32-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
-; CHECK-32-NEXT:    movswl %cx, %eax
-; CHECK-32-NEXT:    sarl $15, %eax
-; CHECK-32-NEXT:    movl {{[0-9]+}}(%esp), %esi
 ; CHECK-32-NEXT:    movl {{[0-9]+}}(%esp), %edi
+; CHECK-32-NEXT:    movl {{[0-9]+}}(%esp), %edx
+; CHECK-32-NEXT:    movzwl {{[0-9]+}}(%esp), %eax
+; CHECK-32-NEXT:    movl %eax, %ecx
 ; CHECK-32-NEXT:    andl $32767, %ecx # imm = 0x7FFF
-; CHECK-32-NEXT:    xorl %edx, %edx
-; CHECK-32-NEXT:    addl $-1, %esi
-; CHECK-32-NEXT:    adcl $-1, %edi
-; CHECK-32-NEXT:    adcl $-1, %ecx
+; CHECK-32-NEXT:    xorl %esi, %esi
+; CHECK-32-NEXT:    addl $-1, %edi
 ; CHECK-32-NEXT:    adcl $-1, %edx
-; CHECK-32-NEXT:    cmpl $-1, %esi
-; CHECK-32-NEXT:    sbbl $2147483647, %edi # imm = 0x7FFFFFFF
+; CHECK-32-NEXT:    adcl $-1, %ecx
+; CHECK-32-NEXT:    adcl $-1, %esi
+; CHECK-32-NEXT:    cmpl $-1, %edi
+; CHECK-32-NEXT:    sbbl $2147483647, %edx # imm = 0x7FFFFFFF
 ; CHECK-32-NEXT:    sbbl $0, %ecx
-; CHECK-32-NEXT:    sbbl $0, %edx
+; CHECK-32-NEXT:    sbbl $0, %esi
 ; CHECK-32-NEXT:    setb %cl
-; CHECK-32-NEXT:    testl %eax, %eax
-; CHECK-32-NEXT:    sets %al
+; CHECK-32-NEXT:    testl $32768, %eax # imm = 0x8000
+; CHECK-32-NEXT:    setne %al
 ; CHECK-32-NEXT:    andb %cl, %al
 ; CHECK-32-NEXT:    popl %esi
 ; CHECK-32-NEXT:    .cfi_def_cfa_offset 8
diff --git a/llvm/test/CodeGen/X86/movmsk-bittest.ll b/llvm/test/CodeGen/X86/movmsk-bittest.ll
index 7c8fe03ff4741..b67e70e71c3d5 100644
--- a/llvm/test/CodeGen/X86/movmsk-bittest.ll
+++ b/llvm/test/CodeGen/X86/movmsk-bittest.ll
@@ -37,18 +37,16 @@ define i32 @movmsk_slt_v2i64_1(<2 x i64> %v, i32 %a, i32 %b) {
 ; SSE:       # %bb.0:
 ; SSE-NEXT:    movl %edi, %eax
 ; SSE-NEXT:    movmskpd %xmm0, %ecx
-; SSE-NEXT:    shlb $6, %cl
-; SSE-NEXT:    sarb $6, %cl
-; SSE-NEXT:    cmovnsl %esi, %eax
+; SSE-NEXT:    testb $2, %cl
+; SSE-NEXT:    cmovel %esi, %eax
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: movmsk_slt_v2i64_1:
 ; AVX:       # %bb.0:
 ; AVX-NEXT:    movl %edi, %eax
 ; AVX-NEXT:    vmovmskpd %xmm0, %ecx
-; AVX-NEXT:    shlb $6, %cl
-; AVX-NEXT:    sarb $6, %cl
-; AVX-NEXT:    cmovnsl %esi, %eax
+; AVX-NEXT:    testb $2, %cl
+; AVX-NEXT:    cmovel %esi, %eax
 ; AVX-NEXT:    retq
   %cmp = icmp slt <2 x i64> %v, zeroinitializer
   %msk = bitcast <2 x i1> %cmp to i2
@@ -62,18 +60,16 @@ define i32 @movmsk_sgt_v2i64_1(<2 x i64> %v, i32 %a, i32 %b) {
 ; SSE:       # %bb.0:
 ; SSE-NEXT:    movl %edi, %eax
 ; SSE-NEXT:    movmskpd %xmm0, %ecx
-; SSE-NEXT:    shlb $6, %cl
-; SSE-NEXT:    sarb $6, %cl
-; SSE-NEXT:    cmovsl %esi, %eax
+; SSE-NEXT:    testb $2, %cl
+; SSE-NEXT:    cmovnel %esi, %eax
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: movmsk_sgt_v2i64_1:
 ; AVX:       # %bb.0:
 ; AVX-NEXT:    movl %edi, %eax
 ; AVX-NEXT:    vmovmskpd %xmm0, %ecx
-; AVX-NEXT:    shlb $6, %cl
-; AVX-NEXT:    sarb $6, %cl
-; AVX-NEXT:    cmovsl %esi, %eax
+; AVX-NEXT:    testb $2, %cl
+; AVX-NEXT:    cmovnel %esi, %eax
 ; AVX-NEXT:    retq
   %cmp = icmp slt <2 x i64> %v, zeroinitializer
   %msk = bitcast <2 x i1> %cmp to i2
@@ -111,18 +107,16 @@ define i32 @movmsk_slt_v4i32_3(<4 x i32> %v, i32 %a, i32 %b) {
 ; SSE:       # %bb.0:
 ; SSE-NEXT:    movl %edi, %eax
 ; SSE-NEXT:    movmskps %xmm0, %ecx
-; SSE-NEXT:    shlb $4, %cl
-; SSE-NEXT:    sarb $4, %cl
-; SSE-NEXT:    cmovnsl %esi, %eax
+; SSE-NEXT:    testb $8, %cl
+; SSE-NEXT:    cmovel %esi, %eax
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: movmsk_slt_v4i32_3:
 ; AVX:       # %bb.0:
 ; AVX-NEXT:    movl %edi, %eax
 ; AVX-NEXT:    vmovmskps %xmm0, %ecx
-; AVX-NEXT:    shlb $4, %cl
-; AVX-NEXT:    sarb $4, %cl
-; AVX-NEXT:    cmovnsl %esi, %eax
+; AVX-NEXT:    testb $8, %cl
+; AVX-NEXT:    cmovel %esi, %eax
 ; AVX-NEXT:    retq
   %cmp = icmp slt <4 x i32> %v, zeroinitializer
   %msk = bitcast <4 x i1> %cmp to i4
@@ -136,18 +130,16 @@ define i32 @movmsk_sgt_v4i32_3(<4 x i32> %v, i32 %a, i32 %b) {
 ; SSE:       # %bb.0:
 ; SSE-NEXT:    movl %edi, %eax
 ; SSE-NEXT:    movmskps %xmm0, %ecx
-; SSE-NEXT:    shlb $4, %cl
-; SSE-NEXT:    sarb $4, %cl
-; SSE-NEXT:    cmovsl %esi, %eax
+; SSE-NEXT:    testb $8, %cl
+; SSE-NEXT:    cmovnel %esi, %eax
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: movmsk_sgt_v4i32_3:
 ; AVX:       # %bb.0:
 ; AVX-NEXT:    movl %edi, %eax
 ; AVX-NEXT:    vmovmskps %xmm0, %ecx
-; AVX-NEXT:    shlb $4, %cl
-; AVX-NEXT:    sarb $4, %cl
-; AVX-NEXT:    cmovsl %esi, %eax
+; AVX-NEXT:    testb $8, %cl
+; AVX-NEXT:    cmovnel %esi, %eax
 ; AVX-NEXT:    retq
   %cmp = icmp slt <4 x i32> %v, zeroinitializer
   %msk = bitcast <4 x i1> %cmp to i4
@@ -256,20 +248,17 @@ define i32 @movmsk_slt_v4i64_3(<4 x i64> %v, i32 %a, i32 %b) {
 ; SSE-LABEL: movmsk_slt_v4i64_3:
 ; SSE:       # %bb.0:
 ; SSE-NEXT:    movl %edi, %eax
-; SSE-NEXT:    shufps {{.*#+}} xmm0 = xmm0[1,3],xmm1[1,3]
-; SSE-NEXT:    movmskps %xmm0, %ecx
-; SSE-NEXT:    shlb $4, %cl
-; SSE-NEXT:    sarb $4, %cl
-; SSE-NEXT:    cmovnsl %esi, %eax
+; SSE-NEXT:    movmskps %xmm1, %ecx
+; SSE-NEXT:    testb $8, %cl
+; SSE-NEXT:    cmovel %esi, %eax
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: movmsk_slt_v4i64_3:
 ; AVX:       # %bb.0:
 ; AVX-NEXT:    movl %edi, %eax
 ; AVX-NEXT:    vmovmskpd %ymm0, %ecx
-; AVX-NEXT:    shlb $4, %cl
-; AVX-NEXT:    sarb $4, %cl
-; AVX-NEXT:    cmovnsl %esi, %eax
+; AVX-NEXT:    testb $8, %cl
+; AVX-NEXT:    cmovel %esi, %eax
 ; AVX-NEXT:    vzeroupper
 ; AVX-NEXT:    retq
   %cmp = icmp slt <4 x i64> %v, zeroinitializer
@@ -283,20 +272,17 @@ define i32 @movmsk_sgt_v4i64_3(<4 x i64> %v, i32 %a, i32 %b) {
 ; SSE-LABEL: movmsk_sgt_v4i64_3:
 ; SSE:       # %bb.0:
 ; SSE-NEXT:    movl %edi, %eax
-; SSE-NEXT:    shufps {{.*#+}} xmm0 = xmm0[1,3],xmm1[1,3]
-; SSE-NEXT:    movmskps %xmm0, %ecx
-; SSE-NEXT:    shlb $4, %cl
-; SSE-NEXT:    sarb $4, %cl
-; SSE-NEXT:    cmovsl %esi, %eax
+; SSE-NEXT:    movmskps %xmm1, %ecx
+; SSE-NEXT:    testb $8, %cl
+; SSE-NEXT:    cmovnel %esi, %eax
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: movmsk_sgt_v4i64_3:
 ; AVX:       # %bb.0:
 ; AVX-NEXT:    movl %edi, %eax
 ; AVX-NEXT:    vmovmskpd %ymm0, %ecx
-; AVX-NEXT:    shlb $4, %cl
-; AVX-NEXT:    sarb $4, %cl
-; AVX-NEXT:    cmovsl %esi, %eax
+; AVX-NEXT:    testb $8, %cl
+; AVX-NEXT:    cmovnel %esi, %eax
 ; AVX-NEXT:    vzeroupper
 ; AVX-NEXT:    retq
   %cmp = icmp slt <4 x i64> %v, zeroinitializer
@@ -487,22 +473,18 @@ define i32 @movmsk_slt_v32i8_31(<32 x i8> %v, i32 %a, i32 %b) {
 ; SSE-LABEL: movmsk_slt_v32i8_31:
 ; SSE:       # %bb.0:
 ; SSE-NEXT:    movl %edi, %eax
-; SSE-NEXT:    pmovmskb %xmm0, %ecx
-; SSE-NEXT:    pmovmskb %xmm1, %edx
-; SSE-NEXT:    shll $16, %edx
-; SSE-NEXT:    orl %ecx, %edx
-; SSE-NEXT:    cmovnsl %esi, %eax
+; SSE-NEXT:    pmovmskb %xmm1, %ecx
+; SSE-NEXT:    testl $32768, %ecx # imm = 0x8000
+; SSE-NEXT:    cmovel %esi, %eax
 ; SSE-NEXT:    retq
 ;
 ; AVX1-LABEL: movmsk_slt_v32i8_31:
 ; AVX1:       # %bb.0:
 ; AVX1-NEXT:    movl %edi, %eax
-; AVX1-NEXT:    vpmovmskb %xmm0, %ecx
 ; AVX1-NEXT:    vextractf128 $1, %ymm0, %xmm0
-; AVX1-NEXT:    vpmovmskb %xmm0, %edx
-; AVX1-NEXT:    shll $16, %edx
-; AVX1-NEXT:    orl %ecx, %edx
-; AVX1-NEXT:    cmovnsl %esi, %eax
+; AVX1-NEXT:    vpmovmskb %xmm0, %ecx
+; AVX1-NEXT:    testl $32768, %ecx # imm = 0x8000
+; AVX1-NEXT:    cmovel %esi, %eax
 ; AVX1-NEXT:    vzeroupper
 ; AVX1-NEXT:    retq
 ;
@@ -534,22 +516,18 @@ define i32 @movmsk_sgt_v32i8_31(<32 x i8> %v, i32 %a, i32 %b) {
 ; SSE-LABEL: movmsk_sgt_v32i8_31:
 ; SSE:       # %bb.0:
 ; SSE-NEXT:    movl %edi, %eax
-; SSE-NEXT:    pmovmskb %xmm0, %ecx
-; SSE-NEXT:    pmovmskb %xmm1, %edx
-; SSE-NEXT:    shll $16, %edx
-; SSE-NEXT:    orl %ecx, %edx
-; SSE-NEXT:    cmovsl %esi, %eax
+; SSE-NEXT:    pmovmskb %xmm1, %ecx
+; SSE-NEXT:    testl $32768, %ecx # imm = 0x8000
+; SSE-NEXT:    cmovnel %esi, %eax
 ; SSE-NEXT:    retq
 ;
 ; AVX1-LABEL: movmsk_sgt_v32i8_31:
 ; AVX1:       # %bb.0:
 ; AVX1-NEXT:    movl %edi, %eax
-; AVX1-NEXT:    vpmovmskb %xmm0, %ecx
 ; AVX1-NEXT:    vextractf128 $1, %ymm0, %xmm0
-; AVX1-NEXT:    vpmovmskb %xmm0, %edx
-; AVX1-NEXT:    shll $16, %edx
-; AVX1-NEXT:    orl %ecx, %edx
-; AVX1-NEXT:    cmovsl %esi, %eax
+; AVX1-NEXT:    vpmovmskb %xmm0, %ecx
+; AVX1-NEXT:    testl $32768, %ecx # imm = 0x8000
+; AVX1-NEXT:    cmovnel %esi, %eax
 ; AVX1-NEXT:    vzeroupper
 ; AVX1-NEXT:    retq
 ;