[llvm] r350194 - [X86] Add test cases to show where LowerSELECT doesn't select SADDO/SSUBO to INC/DEC, but LowerXALUOOp does. Leading to duplicate code.

[Craig Topper via llvm-commits]

Author: ctopper
Date: Tue Jan  1 10:44:42 2019
New Revision: 350194

URL: http://llvm.org/viewvc/llvm-project?rev=350194&view=rev
Log:
[X86] Add test cases to show where LowerSELECT doesn't select SADDO/SSUBO to INC/DEC, but LowerXALUOOp does. Leading to duplicate code.

When SADDO/SSUBO is used as a part of a condition, the X86 backend has to lower the instruction twice. One for the flags use and then once for the data use. These two selections should be kept in sync so they end up with one node providing the data and the flags. This doesn't seem to be happening for INC/DEC.

Modified:
    llvm/trunk/test/CodeGen/X86/xaluo.ll

Modified: llvm/trunk/test/CodeGen/X86/xaluo.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/xaluo.ll?rev=350194&r1=350193&r2=350194&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/xaluo.ll (original)
+++ llvm/trunk/test/CodeGen/X86/xaluo.ll Tue Jan  1 10:44:42 2019
@@ -1405,6 +1405,85 @@ define {i64, i1} @usuboovf(i64 %a, i64 %
   ret {i64, i1} %t
 }
 
+; FIXME: We're selecting both an INC and an ADD here. One of them becomes an LEA.
+define i32 @incovfselectstore(i32 %v1, i32 %v2, i32* %x) {
+; SDAG-LABEL: incovfselectstore:
+; SDAG:       ## %bb.0:
+; SDAG-NEXT:    movl %esi, %eax
+; SDAG-NEXT:    ## kill: def $edi killed $edi def $rdi
+; SDAG-NEXT:    leal 1(%rdi), %ecx
+; SDAG-NEXT:    movl %edi, %esi
+; SDAG-NEXT:    addl $1, %esi
+; SDAG-NEXT:    cmovol %edi, %eax
+; SDAG-NEXT:    movl %ecx, (%rdx)
+; SDAG-NEXT:    retq
+;
+; FAST-LABEL: incovfselectstore:
+; FAST:       ## %bb.0:
+; FAST-NEXT:    movl %esi, %eax
+; FAST-NEXT:    movl %edi, %ecx
+; FAST-NEXT:    incl %ecx
+; FAST-NEXT:    cmovol %edi, %eax
+; FAST-NEXT:    movl %ecx, (%rdx)
+; FAST-NEXT:    retq
+;
+; KNL-LABEL: incovfselectstore:
+; KNL:       ## %bb.0:
+; KNL-NEXT:    movl %esi, %eax
+; KNL-NEXT:    ## kill: def $edi killed $edi def $rdi
+; KNL-NEXT:    leal 1(%rdi), %ecx
+; KNL-NEXT:    movl %edi, %esi
+; KNL-NEXT:    addl $1, %esi
+; KNL-NEXT:    cmovol %edi, %eax
+; KNL-NEXT:    movl %ecx, (%rdx)
+; KNL-NEXT:    retq
+  %t = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %v1, i32 1)
+  %obit = extractvalue {i32, i1} %t, 1
+  %ret = select i1 %obit, i32 %v1, i32 %v2
+  %val = extractvalue {i32, i1} %t, 0
+  store i32 %val, i32* %x
+  ret i32 %ret
+}
+
+; FIXME: We're selecting both a DEC and a SUB here. DEC becomes an LEA and
+; SUB becomes a CMP.
+define i32 @decovfselectstore(i32 %v1, i32 %v2, i32* %x) {
+; SDAG-LABEL: decovfselectstore:
+; SDAG:       ## %bb.0:
+; SDAG-NEXT:    movl %esi, %eax
+; SDAG-NEXT:    ## kill: def $edi killed $edi def $rdi
+; SDAG-NEXT:    leal -1(%rdi), %ecx
+; SDAG-NEXT:    cmpl $1, %edi
+; SDAG-NEXT:    cmovol %edi, %eax
+; SDAG-NEXT:    movl %ecx, (%rdx)
+; SDAG-NEXT:    retq
+;
+; FAST-LABEL: decovfselectstore:
+; FAST:       ## %bb.0:
+; FAST-NEXT:    movl %esi, %eax
+; FAST-NEXT:    movl %edi, %ecx
+; FAST-NEXT:    decl %ecx
+; FAST-NEXT:    cmovol %edi, %eax
+; FAST-NEXT:    movl %ecx, (%rdx)
+; FAST-NEXT:    retq
+;
+; KNL-LABEL: decovfselectstore:
+; KNL:       ## %bb.0:
+; KNL-NEXT:    movl %esi, %eax
+; KNL-NEXT:    ## kill: def $edi killed $edi def $rdi
+; KNL-NEXT:    leal -1(%rdi), %ecx
+; KNL-NEXT:    cmpl $1, %edi
+; KNL-NEXT:    cmovol %edi, %eax
+; KNL-NEXT:    movl %ecx, (%rdx)
+; KNL-NEXT:    retq
+  %t = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %v1, i32 1)
+  %obit = extractvalue {i32, i1} %t, 1
+  %ret = select i1 %obit, i32 %v1, i32 %v2
+  %val = extractvalue {i32, i1} %t, 0
+  store i32 %val, i32* %x
+  ret i32 %ret
+}
+
 declare {i8,  i1} @llvm.sadd.with.overflow.i8 (i8,  i8 ) nounwind readnone
 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16, i16) nounwind readnone
 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32, i32) nounwind readnone