[CGP][x86] add tests for usubo special-case; NFC

This is another example from PR31754:
https://bugs.llvm.org/show_bug.cgi?id=31754

llvm-svn: 354475

2 files changed, 41 insertions, 9 deletions

diff --git a/llvm/test/CodeGen/X86/cgp-usubo.ll b/llvm/test/CodeGen/X86/cgp-usubo.ll
index 3554f19fcfe..ba804282364 100644
--- a/llvm/test/CodeGen/X86/cgp-usubo.ll
+++ b/llvm/test/CodeGen/X86/cgp-usubo.ll
@@ -106,6 +106,23 @@ define i1 @usubo_eq_constant1_op1_i32(i32 %x, i32* %p) nounwind {
   ret i1 %ov
 }
 
+; Special-case: subtract from 0 (negate) changes the compare predicate.
+
+define i1 @usubo_ne_constant0_op1_i32(i32 %x, i32* %p) {
+; CHECK-LABEL: usubo_ne_constant0_op1_i32:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    movl %edi, %ecx
+; CHECK-NEXT:    negl %ecx
+; CHECK-NEXT:    testl %edi, %edi
+; CHECK-NEXT:    setne %al
+; CHECK-NEXT:    movl %ecx, (%rsi)
+; CHECK-NEXT:    retq
+  %s = sub i32 0, %x
+  %ov = icmp ne i32 %x, 0
+  store i32 %s, i32* %p
+  ret i1 %ov
+}
+
 ; Verify insertion point for multi-BB.
 
 declare void @call(i1)
@@ -114,16 +131,16 @@ define i1 @usubo_ult_sub_dominates_i64(i64 %x, i64 %y, i64* %p, i1 %cond) nounwi
 ; CHECK-LABEL: usubo_ult_sub_dominates_i64:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    testb $1, %cl
-; CHECK-NEXT:    je .LBB7_2
+; CHECK-NEXT:    je .LBB8_2
 ; CHECK-NEXT:  # %bb.1: # %t
 ; CHECK-NEXT:    subq %rsi, %rdi
 ; CHECK-NEXT:    setb %al
 ; CHECK-NEXT:    movq %rdi, (%rdx)
 ; CHECK-NEXT:    testb $1, %cl
-; CHECK-NEXT:    jne .LBB7_3
-; CHECK-NEXT:  .LBB7_2: # %f
+; CHECK-NEXT:    jne .LBB8_3
+; CHECK-NEXT:  .LBB8_2: # %f
 ; CHECK-NEXT:    movl %ecx, %eax
-; CHECK-NEXT:  .LBB7_3: # %end
+; CHECK-NEXT:  .LBB8_3: # %end
 ; CHECK-NEXT:    retq
 entry:
   br i1 %cond, label %t, label %f
@@ -151,7 +168,7 @@ define i1 @usubo_ult_cmp_dominates_i64(i64 %x, i64 %y, i64* %p, i1 %cond) nounwi
 ; CHECK-NEXT:    pushq %rax
 ; CHECK-NEXT:    movl %ecx, %ebp
 ; CHECK-NEXT:    testb $1, %bpl
-; CHECK-NEXT:    je .LBB8_2
+; CHECK-NEXT:    je .LBB9_2
 ; CHECK-NEXT:  # %bb.1: # %t
 ; CHECK-NEXT:    movq %rdx, %r14
 ; CHECK-NEXT:    movq %rsi, %r15
@@ -161,14 +178,14 @@ define i1 @usubo_ult_cmp_dominates_i64(i64 %x, i64 %y, i64* %p, i1 %cond) nounwi
 ; CHECK-NEXT:    setb %dil
 ; CHECK-NEXT:    callq call
 ; CHECK-NEXT:    subq %r15, %rbx
-; CHECK-NEXT:    jae .LBB8_2
+; CHECK-NEXT:    jae .LBB9_2
 ; CHECK-NEXT:  # %bb.4: # %end
 ; CHECK-NEXT:    setb %al
 ; CHECK-NEXT:    movq %rbx, (%r14)
-; CHECK-NEXT:    jmp .LBB8_3
-; CHECK-NEXT:  .LBB8_2: # %f
+; CHECK-NEXT:    jmp .LBB9_3
+; CHECK-NEXT:  .LBB9_2: # %f
 ; CHECK-NEXT:    movl %ebp, %eax
-; CHECK-NEXT:  .LBB8_3: # %f
+; CHECK-NEXT:  .LBB9_3: # %f
 ; CHECK-NEXT:    addq $8, %rsp
 ; CHECK-NEXT:    popq %rbx
 ; CHECK-NEXT:    popq %r14
diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll b/llvm/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll
index 4661106a89e..5107e833ecf 100644
--- a/llvm/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/overflow-intrinsics.ll
@@ -281,6 +281,21 @@ define i1 @usubo_eq_constant1_op1_i32(i32 %x, i32* %p) {
   ret i1 %ov
 }
 
+; Special-case: subtract from 0 (negate) changes the compare predicate.
+
+define i1 @usubo_ne_constant0_op1_i32(i32 %x, i32* %p) {
+; CHECK-LABEL: @usubo_ne_constant0_op1_i32(
+; CHECK-NEXT:    [[S:%.*]] = sub i32 0, [[X:%.*]]
+; CHECK-NEXT:    [[OV:%.*]] = icmp ne i32 [[X]], 0
+; CHECK-NEXT:    store i32 [[S]], i32* [[P:%.*]]
+; CHECK-NEXT:    ret i1 [[OV]]
+;
+  %s = sub i32 0, %x
+  %ov = icmp ne i32 %x, 0
+  store i32 %s, i32* %p
+  ret i1 %ov
+}
+
 ; Verify insertion point for multi-BB.
 
 declare void @call(i1)