[llvm] r310490 - [x86] add more tests for select-of-constants; NFC
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Wed Aug 9 08:57:02 PDT 2017
Author: spatel
Date: Wed Aug 9 08:57:02 2017
New Revision: 310490
URL: http://llvm.org/viewvc/llvm-project?rev=310490&view=rev
Log:
[x86] add more tests for select-of-constants; NFC
This is to help recommit a fixed version of r310208. As shown in PR34097,
we could miscompile if subtraction of the constants overflowed.
Modified:
llvm/trunk/test/CodeGen/X86/select_const.ll
Modified: llvm/trunk/test/CodeGen/X86/select_const.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/select_const.ll?rev=310490&r1=310489&r2=310490&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/select_const.ll (original)
+++ llvm/trunk/test/CodeGen/X86/select_const.ll Wed Aug 9 08:57:02 2017
@@ -256,6 +256,79 @@ define i64 @select_lea_9(i1 zeroext %con
ret i64 %sel
}
+; Should this be 'sbb x,x' or 'sbb 0,x' with simpler LEA or add?
+
+define i64 @sel_1_2(i64 %x, i64 %y) {
+; CHECK-LABEL: sel_1_2:
+; CHECK: # BB#0:
+; CHECK-NEXT: cmpq $42, %rdi
+; CHECK-NEXT: sbbq %rax, %rax
+; CHECK-NEXT: leaq 2(%rax,%rsi), %rax
+; CHECK-NEXT: retq
+ %cmp = icmp ult i64 %x, 42
+ %sel = select i1 %cmp, i64 1, i64 2
+ %sub = add i64 %sel, %y
+ ret i64 %sub
+}
+
+; No LEA with 8-bit or 16-bit, but this shouldn't need branches or cmov.
+
+define i8 @sel_1_neg1(i32 %x) {
+; CHECK-LABEL: sel_1_neg1:
+; CHECK: # BB#0:
+; CHECK-NEXT: cmpl $42, %edi
+; CHECK-NEXT: movb $3, %al
+; CHECK-NEXT: jg .LBB23_2
+; CHECK-NEXT: # BB#1:
+; CHECK-NEXT: movb $-1, %al
+; CHECK-NEXT: .LBB23_2:
+; CHECK-NEXT: retq
+ %cmp = icmp sgt i32 %x, 42
+ %sel = select i1 %cmp, i8 3, i8 -1
+ ret i8 %sel
+}
+
+define i16 @sel_neg1_1(i32 %x) {
+; CHECK-LABEL: sel_neg1_1:
+; CHECK: # BB#0:
+; CHECK-NEXT: cmpl $42, %edi
+; CHECK-NEXT: movw $-1, %cx
+; CHECK-NEXT: movw $3, %ax
+; CHECK-NEXT: cmovgw %cx, %ax
+; CHECK-NEXT: retq
+ %cmp = icmp sgt i32 %x, 42
+ %sel = select i1 %cmp, i16 -1, i16 3
+ ret i16 %sel
+}
+
+; If the comparison is available, the predicate can be inverted.
+
+define i32 @sel_1_neg1_32(i32 %x) {
+; CHECK-LABEL: sel_1_neg1_32:
+; CHECK: # BB#0:
+; CHECK-NEXT: cmpl $42, %edi
+; CHECK-NEXT: movl $8, %ecx
+; CHECK-NEXT: movl $-1, %eax
+; CHECK-NEXT: cmovgl %ecx, %eax
+; CHECK-NEXT: retq
+ %cmp = icmp sgt i32 %x, 42
+ %sel = select i1 %cmp, i32 8, i32 -1
+ ret i32 %sel
+}
+
+define i32 @sel_neg1_1_32(i32 %x) {
+; CHECK-LABEL: sel_neg1_1_32:
+; CHECK: # BB#0:
+; CHECK-NEXT: cmpl $42, %edi
+; CHECK-NEXT: movl $-7, %ecx
+; CHECK-NEXT: movl $2, %eax
+; CHECK-NEXT: cmovgl %ecx, %eax
+; CHECK-NEXT: retq
+ %cmp = icmp sgt i32 %x, 42
+ %sel = select i1 %cmp, i32 -7, i32 2
+ ret i32 %sel
+}
+
; If the constants differ by a large power-of-2, that can be a shift of the difference plus the smaller constant.
; select Cond, C1, C2 --> add (mul (zext Cond), C1-C2), C2
@@ -265,10 +338,10 @@ define i8 @select_pow2_diff(i1 zeroext %
; CHECK: # BB#0:
; CHECK-NEXT: testb %dil, %dil
; CHECK-NEXT: movb $19, %al
-; CHECK-NEXT: jne .LBB22_2
+; CHECK-NEXT: jne .LBB27_2
; CHECK-NEXT: # BB#1:
; CHECK-NEXT: movb $3, %al
-; CHECK-NEXT: .LBB22_2:
+; CHECK-NEXT: .LBB27_2:
; CHECK-NEXT: retq
%sel = select i1 %cond, i8 19, i8 3
ret i8 %sel
@@ -310,6 +383,24 @@ define i64 @select_pow2_diff_neg_invert(
ret i64 %sel
}
+; This doesn't need a branch, but don't do the wrong thing if subtraction of the constants overflows.
+
+define i8 @sel_67_neg125(i32 %x) {
+; CHECK-LABEL: sel_67_neg125:
+; CHECK: # BB#0:
+; CHECK-NEXT: cmpl $42, %edi
+; CHECK-NEXT: movb $67, %al
+; CHECK-NEXT: jg .LBB31_2
+; CHECK-NEXT: # BB#1:
+; CHECK-NEXT: movb $-125, %al
+; CHECK-NEXT: .LBB31_2:
+; CHECK-NEXT: retq
+ %cmp = icmp sgt i32 %x, 42
+ %sel = select i1 %cmp, i8 67, i8 -125
+ ret i8 %sel
+}
+
+
; In general, select of 2 constants could be:
; select Cond, C1, C2 --> add (mul (zext Cond), C1-C2), C2 --> add (and (sext Cond), C1-C2), C2
@@ -368,11 +459,11 @@ define <4 x i32> @sel_constants_add_cons
; CHECK-LABEL: sel_constants_add_constant_vec:
; CHECK: # BB#0:
; CHECK-NEXT: testb $1, %dil
-; CHECK-NEXT: jne .LBB30_1
+; CHECK-NEXT: jne .LBB36_1
; CHECK-NEXT: # BB#2:
; CHECK-NEXT: movaps {{.*#+}} xmm0 = [12,13,14,15]
; CHECK-NEXT: retq
-; CHECK-NEXT: .LBB30_1:
+; CHECK-NEXT: .LBB36_1:
; CHECK-NEXT: movaps {{.*#+}} xmm0 = [4294967293,14,4,4]
; CHECK-NEXT: retq
%sel = select i1 %cond, <4 x i32> <i32 -4, i32 12, i32 1, i32 0>, <4 x i32> <i32 11, i32 11, i32 11, i32 11>
@@ -384,11 +475,11 @@ define <2 x double> @sel_constants_fmul_
; CHECK-LABEL: sel_constants_fmul_constant_vec:
; CHECK: # BB#0:
; CHECK-NEXT: testb $1, %dil
-; CHECK-NEXT: jne .LBB31_1
+; CHECK-NEXT: jne .LBB37_1
; CHECK-NEXT: # BB#2:
; CHECK-NEXT: movaps {{.*#+}} xmm0 = [1.188300e+02,3.454000e+01]
; CHECK-NEXT: retq
-; CHECK-NEXT: .LBB31_1:
+; CHECK-NEXT: .LBB37_1:
; CHECK-NEXT: movaps {{.*#+}} xmm0 = [-2.040000e+01,3.768000e+01]
; CHECK-NEXT: retq
%sel = select i1 %cond, <2 x double> <double -4.0, double 12.0>, <2 x double> <double 23.3, double 11.0>
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