[X86] Teach EmitTest to handle ISD::SSUBO/USUBO in order to use the Z flag from the subtract directly during isel.

This prevents isel from emitting a TEST instruction that
optimizeCompareInstr will need to remove later.

In some of the modified tests, the SUB gets duplicated due to
the flags being needed in two places and being clobbered in
between. optimizeCompareInstr was able to optimize away the TEST
that was using the result of one of them, but optimizeCompareInstr
doesn't know to turn SUB into CMP after removing the TEST. It
only knows how to turn SUB into CMP if the result was already
dead.

With this change the TEST never exists, so optimizeCompareInstr
doesn't have to remove it. Then it can just turn the SUB into
CMP immediately.

Fixes PR43649.

llvm-svn: 374755

3 files changed, 34 insertions, 61 deletions

diff --git a/llvm/test/CodeGen/X86/known-bits.ll b/llvm/test/CodeGen/X86/known-bits.ll
index d9a7921131f..8e2e9c05fdc 100644
--- a/llvm/test/CodeGen/X86/known-bits.ll
+++ b/llvm/test/CodeGen/X86/known-bits.ll
@@ -190,26 +190,22 @@ define {i32, i1} @knownbits_uaddo_saddo(i64 %a0, i64 %a1) nounwind {
 define {i32, i1} @knownbits_usubo_ssubo(i64 %a0, i64 %a1) nounwind {
 ; X32-LABEL: knownbits_usubo_ssubo:
 ; X32:       # %bb.0:
-; X32-NEXT:    pushl %ebx
 ; X32-NEXT:    movl {{[0-9]+}}(%esp), %eax
 ; X32-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; X32-NEXT:    movl %ecx, %edx
-; X32-NEXT:    subl %eax, %edx
-; X32-NEXT:    setb %bl
-; X32-NEXT:    testl %eax, %eax
-; X32-NEXT:    setns %al
+; X32-NEXT:    cmpl %eax, %ecx
+; X32-NEXT:    setb %dh
+; X32-NEXT:    setns %dl
 ; X32-NEXT:    testl %ecx, %ecx
 ; X32-NEXT:    setns %cl
-; X32-NEXT:    cmpb %al, %cl
-; X32-NEXT:    setne %al
-; X32-NEXT:    testl %edx, %edx
-; X32-NEXT:    setns %dl
 ; X32-NEXT:    cmpb %dl, %cl
+; X32-NEXT:    setne %ch
+; X32-NEXT:    testl %eax, %eax
+; X32-NEXT:    setns %al
+; X32-NEXT:    cmpb %al, %cl
 ; X32-NEXT:    setne %dl
-; X32-NEXT:    andb %al, %dl
-; X32-NEXT:    orb %bl, %dl
+; X32-NEXT:    andb %ch, %dl
+; X32-NEXT:    orb %dh, %dl
 ; X32-NEXT:    xorl %eax, %eax
-; X32-NEXT:    popl %ebx
 ; X32-NEXT:    retl
 ;
 ; X64-LABEL: knownbits_usubo_ssubo:
diff --git a/llvm/test/CodeGen/X86/ssub_sat.ll b/llvm/test/CodeGen/X86/ssub_sat.ll
index 62724e981f7..51ca6d8a794 100644
--- a/llvm/test/CodeGen/X86/ssub_sat.ll
+++ b/llvm/test/CodeGen/X86/ssub_sat.ll
@@ -12,24 +12,20 @@ declare <4 x i32> @llvm.ssub.sat.v4i32(<4 x i32>, <4 x i32>)
 define i32 @func(i32 %x, i32 %y) nounwind {
 ; X86-LABEL: func:
 ; X86:       # %bb.0:
-; X86-NEXT:    pushl %esi
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %edx
 ; X86-NEXT:    xorl %ecx, %ecx
-; X86-NEXT:    movl %eax, %esi
-; X86-NEXT:    subl %edx, %esi
+; X86-NEXT:    cmpl %edx, %eax
 ; X86-NEXT:    setns %cl
 ; X86-NEXT:    addl $2147483647, %ecx # imm = 0x7FFFFFFF
 ; X86-NEXT:    subl %edx, %eax
 ; X86-NEXT:    cmovol %ecx, %eax
-; X86-NEXT:    popl %esi
 ; X86-NEXT:    retl
 ;
 ; X64-LABEL: func:
 ; X64:       # %bb.0:
 ; X64-NEXT:    xorl %eax, %eax
-; X64-NEXT:    movl %edi, %ecx
-; X64-NEXT:    subl %esi, %ecx
+; X64-NEXT:    cmpl %esi, %edi
 ; X64-NEXT:    setns %al
 ; X64-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
 ; X64-NEXT:    subl %esi, %edi
@@ -79,8 +75,7 @@ define i64 @func2(i64 %x, i64 %y) nounwind {
 ; X64-LABEL: func2:
 ; X64:       # %bb.0:
 ; X64-NEXT:    xorl %ecx, %ecx
-; X64-NEXT:    movq %rdi, %rax
-; X64-NEXT:    subq %rsi, %rax
+; X64-NEXT:    cmpq %rsi, %rdi
 ; X64-NEXT:    setns %cl
 ; X64-NEXT:    movabsq $9223372036854775807, %rax # imm = 0x7FFFFFFFFFFFFFFF
 ; X64-NEXT:    addq %rcx, %rax
@@ -94,25 +89,21 @@ define i64 @func2(i64 %x, i64 %y) nounwind {
 define i16 @func16(i16 %x, i16 %y) nounwind {
 ; X86-LABEL: func16:
 ; X86:       # %bb.0:
-; X86-NEXT:    pushl %esi
 ; X86-NEXT:    movzwl {{[0-9]+}}(%esp), %eax
 ; X86-NEXT:    movzwl {{[0-9]+}}(%esp), %edx
 ; X86-NEXT:    xorl %ecx, %ecx
-; X86-NEXT:    movl %eax, %esi
-; X86-NEXT:    subw %dx, %si
+; X86-NEXT:    cmpw %dx, %ax
 ; X86-NEXT:    setns %cl
 ; X86-NEXT:    addl $32767, %ecx # imm = 0x7FFF
 ; X86-NEXT:    subw %dx, %ax
 ; X86-NEXT:    cmovol %ecx, %eax
 ; X86-NEXT:    # kill: def $ax killed $ax killed $eax
-; X86-NEXT:    popl %esi
 ; X86-NEXT:    retl
 ;
 ; X64-LABEL: func16:
 ; X64:       # %bb.0:
 ; X64-NEXT:    xorl %eax, %eax
-; X64-NEXT:    movl %edi, %ecx
-; X64-NEXT:    subw %si, %cx
+; X64-NEXT:    cmpw %si, %di
 ; X64-NEXT:    setns %al
 ; X64-NEXT:    addl $32767, %eax # imm = 0x7FFF
 ; X64-NEXT:    subw %si, %di
@@ -129,8 +120,7 @@ define i8 @func8(i8 %x, i8 %y) nounwind {
 ; X86-NEXT:    movb {{[0-9]+}}(%esp), %al
 ; X86-NEXT:    movb {{[0-9]+}}(%esp), %dl
 ; X86-NEXT:    xorl %ecx, %ecx
-; X86-NEXT:    movb %al, %ah
-; X86-NEXT:    subb %dl, %ah
+; X86-NEXT:    cmpb %dl, %al
 ; X86-NEXT:    setns %cl
 ; X86-NEXT:    addl $127, %ecx
 ; X86-NEXT:    subb %dl, %al
@@ -142,8 +132,7 @@ define i8 @func8(i8 %x, i8 %y) nounwind {
 ; X64-LABEL: func8:
 ; X64:       # %bb.0:
 ; X64-NEXT:    xorl %ecx, %ecx
-; X64-NEXT:    movl %edi, %eax
-; X64-NEXT:    subb %sil, %al
+; X64-NEXT:    cmpb %sil, %dil
 ; X64-NEXT:    setns %cl
 ; X64-NEXT:    addl $127, %ecx
 ; X64-NEXT:    subb %sil, %dil
@@ -163,8 +152,7 @@ define i4 @func3(i4 %x, i4 %y) nounwind {
 ; X86-NEXT:    shlb $4, %dl
 ; X86-NEXT:    shlb $4, %al
 ; X86-NEXT:    xorl %ecx, %ecx
-; X86-NEXT:    movb %al, %ah
-; X86-NEXT:    subb %dl, %ah
+; X86-NEXT:    cmpb %dl, %al
 ; X86-NEXT:    setns %cl
 ; X86-NEXT:    addl $127, %ecx
 ; X86-NEXT:    subb %dl, %al
@@ -179,8 +167,7 @@ define i4 @func3(i4 %x, i4 %y) nounwind {
 ; X64-NEXT:    shlb $4, %sil
 ; X64-NEXT:    shlb $4, %dil
 ; X64-NEXT:    xorl %ecx, %ecx
-; X64-NEXT:    movl %edi, %eax
-; X64-NEXT:    subb %sil, %al
+; X64-NEXT:    cmpb %sil, %dil
 ; X64-NEXT:    setns %cl
 ; X64-NEXT:    addl $127, %ecx
 ; X64-NEXT:    subb %sil, %dil
@@ -196,15 +183,13 @@ define i4 @func3(i4 %x, i4 %y) nounwind {
 define <4 x i32> @vec(<4 x i32> %x, <4 x i32> %y) nounwind {
 ; X86-LABEL: vec:
 ; X86:       # %bb.0:
-; X86-NEXT:    pushl %ebp
 ; X86-NEXT:    pushl %ebx
 ; X86-NEXT:    pushl %edi
 ; X86-NEXT:    pushl %esi
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %edx
 ; X86-NEXT:    xorl %eax, %eax
-; X86-NEXT:    movl %ecx, %esi
-; X86-NEXT:    subl %edx, %esi
+; X86-NEXT:    cmpl %edx, %ecx
 ; X86-NEXT:    setns %al
 ; X86-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
 ; X86-NEXT:    subl %edx, %ecx
@@ -212,8 +197,7 @@ define <4 x i32> @vec(<4 x i32> %x, <4 x i32> %y) nounwind {
 ; X86-NEXT:    cmovol %eax, %ecx
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %esi
 ; X86-NEXT:    xorl %eax, %eax
-; X86-NEXT:    movl %edx, %edi
-; X86-NEXT:    subl %esi, %edi
+; X86-NEXT:    cmpl %esi, %edx
 ; X86-NEXT:    setns %al
 ; X86-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
 ; X86-NEXT:    subl %esi, %edx
@@ -221,8 +205,7 @@ define <4 x i32> @vec(<4 x i32> %x, <4 x i32> %y) nounwind {
 ; X86-NEXT:    cmovol %eax, %edx
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %edi
 ; X86-NEXT:    xorl %eax, %eax
-; X86-NEXT:    movl %esi, %ebx
-; X86-NEXT:    subl %edi, %ebx
+; X86-NEXT:    cmpl %edi, %esi
 ; X86-NEXT:    setns %al
 ; X86-NEXT:    addl $2147483647, %eax # imm = 0x7FFFFFFF
 ; X86-NEXT:    subl %edi, %esi
@@ -230,8 +213,7 @@ define <4 x i32> @vec(<4 x i32> %x, <4 x i32> %y) nounwind {
 ; X86-NEXT:    cmovol %eax, %esi
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
 ; X86-NEXT:    xorl %ebx, %ebx
-; X86-NEXT:    movl %edi, %ebp
-; X86-NEXT:    subl %eax, %ebp
+; X86-NEXT:    cmpl %eax, %edi
 ; X86-NEXT:    setns %bl
 ; X86-NEXT:    addl $2147483647, %ebx # imm = 0x7FFFFFFF
 ; X86-NEXT:    subl %eax, %edi
@@ -244,7 +226,6 @@ define <4 x i32> @vec(<4 x i32> %x, <4 x i32> %y) nounwind {
 ; X86-NEXT:    popl %esi
 ; X86-NEXT:    popl %edi
 ; X86-NEXT:    popl %ebx
-; X86-NEXT:    popl %ebp
 ; X86-NEXT:    retl $4
 ;
 ; X64-LABEL: vec:
diff --git a/llvm/test/CodeGen/X86/ssub_sat_vec.ll b/llvm/test/CodeGen/X86/ssub_sat_vec.ll
index 43e8fca8304..73fbb7c0029 100644
--- a/llvm/test/CodeGen/X86/ssub_sat_vec.ll
+++ b/llvm/test/CodeGen/X86/ssub_sat_vec.ll
@@ -408,30 +408,28 @@ define void @v12i16(<12 x i16>* %px, <12 x i16>* %py, <12 x i16>* %pz) nounwind
 define void @v1i8(<1 x i8>* %px, <1 x i8>* %py, <1 x i8>* %pz) nounwind {
 ; SSE-LABEL: v1i8:
 ; SSE:       # %bb.0:
-; SSE-NEXT:    movb (%rdi), %cl
-; SSE-NEXT:    movb (%rsi), %dil
+; SSE-NEXT:    movb (%rdi), %al
+; SSE-NEXT:    movb (%rsi), %cl
 ; SSE-NEXT:    xorl %esi, %esi
-; SSE-NEXT:    movl %ecx, %eax
-; SSE-NEXT:    subb %dil, %al
+; SSE-NEXT:    cmpb %cl, %al
 ; SSE-NEXT:    setns %sil
 ; SSE-NEXT:    addl $127, %esi
-; SSE-NEXT:    subb %dil, %cl
-; SSE-NEXT:    movzbl %cl, %eax
+; SSE-NEXT:    subb %cl, %al
+; SSE-NEXT:    movzbl %al, %eax
 ; SSE-NEXT:    cmovol %esi, %eax
 ; SSE-NEXT:    movb %al, (%rdx)
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: v1i8:
 ; AVX:       # %bb.0:
-; AVX-NEXT:    movb (%rdi), %cl
-; AVX-NEXT:    movb (%rsi), %dil
+; AVX-NEXT:    movb (%rdi), %al
+; AVX-NEXT:    movb (%rsi), %cl
 ; AVX-NEXT:    xorl %esi, %esi
-; AVX-NEXT:    movl %ecx, %eax
-; AVX-NEXT:    subb %dil, %al
+; AVX-NEXT:    cmpb %cl, %al
 ; AVX-NEXT:    setns %sil
 ; AVX-NEXT:    addl $127, %esi
-; AVX-NEXT:    subb %dil, %cl
-; AVX-NEXT:    movzbl %cl, %eax
+; AVX-NEXT:    subb %cl, %al
+; AVX-NEXT:    movzbl %al, %eax
 ; AVX-NEXT:    cmovol %esi, %eax
 ; AVX-NEXT:    movb %al, (%rdx)
 ; AVX-NEXT:    retq
@@ -448,8 +446,7 @@ define void @v1i16(<1 x i16>* %px, <1 x i16>* %py, <1 x i16>* %pz) nounwind {
 ; SSE-NEXT:    movzwl (%rdi), %eax
 ; SSE-NEXT:    movzwl (%rsi), %ecx
 ; SSE-NEXT:    xorl %esi, %esi
-; SSE-NEXT:    movl %eax, %edi
-; SSE-NEXT:    subw %cx, %di
+; SSE-NEXT:    cmpw %cx, %ax
 ; SSE-NEXT:    setns %sil
 ; SSE-NEXT:    addl $32767, %esi # imm = 0x7FFF
 ; SSE-NEXT:    subw %cx, %ax
@@ -462,8 +459,7 @@ define void @v1i16(<1 x i16>* %px, <1 x i16>* %py, <1 x i16>* %pz) nounwind {
 ; AVX-NEXT:    movzwl (%rdi), %eax
 ; AVX-NEXT:    movzwl (%rsi), %ecx
 ; AVX-NEXT:    xorl %esi, %esi
-; AVX-NEXT:    movl %eax, %edi
-; AVX-NEXT:    subw %cx, %di
+; AVX-NEXT:    cmpw %cx, %ax
 ; AVX-NEXT:    setns %sil
 ; AVX-NEXT:    addl $32767, %esi # imm = 0x7FFF
 ; AVX-NEXT:    subw %cx, %ax