[PATCH] D132463: [test] Add more tests for cmp to sbb combination
Paweł Bylica via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 23 04:44:04 PDT 2022
chfast created this revision.
chfast added reviewers: RKSimon, deadalnix, spatel.
Herald added a subscriber: pengfei.
Herald added a project: All.
chfast requested review of this revision.
Herald added a project: LLVM.
Add 2 more tests for potential DAG combine of cmp into sbb.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D132463
Files:
llvm/test/CodeGen/X86/subcarry.ll
Index: llvm/test/CodeGen/X86/subcarry.ll
===================================================================
--- llvm/test/CodeGen/X86/subcarry.ll
+++ llvm/test/CodeGen/X86/subcarry.ll
@@ -652,6 +652,8 @@
ret void
}
+; unsigned less than of two 2x64 integers
+; TODO: This should be optimized to cmp + sbb.
define i1 @subcarry_ult_2x64(i64 %x0, i64 %x1, i64 %y0, i64 %y1) nounwind {
; CHECK-LABEL: subcarry_ult_2x64:
; CHECK: # %bb.0:
@@ -670,3 +672,48 @@
%b1 = or i1 %b10, %b11
ret i1 %b1
}
+
+; New version of subcarry_ult_2x64 after the InstCombine change
+; https://github.com/llvm/llvm-project/commit/926e7312b2f20f2f7b0a3d5ddbd29da5625507f3
+; This is also the result of "naive" implementation (x1 < y1) | ((x0 < y0) & (x1 == y1)).
+; C source: https://godbolt.org/z/W1qqvqGbr
+; TODO: This should be optimized to cmp + sbb.
+define i1 @subcarry_ult_2x64_2(i64 %x0, i64 %x1, i64 %y0, i64 %y1) nounwind {
+; CHECK-LABEL: subcarry_ult_2x64_2:
+; CHECK: # %bb.0: # %entry
+; CHECK-NEXT: cmpq %rdx, %rdi
+; CHECK-NEXT: setb %dl
+; CHECK-NEXT: cmpq %rcx, %rsi
+; CHECK-NEXT: setb %cl
+; CHECK-NEXT: sete %al
+; CHECK-NEXT: andb %dl, %al
+; CHECK-NEXT: orb %cl, %al
+; CHECK-NEXT: retq
+entry:
+ %0 = icmp ult i64 %x0, %y0
+ %1 = icmp ult i64 %x1, %y1
+ %2 = icmp eq i64 %x1, %y1
+ %3 = and i1 %0, %2
+ %4 = or i1 %1, %3
+ ret i1 %4
+}
+
+; unsigned less than of 2x64 and i64 integers
+; The IR comes from C source that uses __builtin_subcl but also the naive version (x0 < y) & (x1 == 0).
+; https://godbolt.org/z/W1qqvqGbr
+; TODO: This should be optimized to cmp + sbb.
+define i1 @subcarry_ult_2x64_1x64(i64 %x0, i64 %x1, i64 %y) nounwind {
+; CHECK-LABEL: subcarry_ult_2x64_1x64:
+; CHECK: # %bb.0: # %entry
+; CHECK-NEXT: cmpq %rdx, %rdi
+; CHECK-NEXT: setb %cl
+; CHECK-NEXT: testq %rsi, %rsi
+; CHECK-NEXT: sete %al
+; CHECK-NEXT: andb %cl, %al
+; CHECK-NEXT: retq
+entry:
+ %0 = icmp ult i64 %x0, %y
+ %1 = icmp eq i64 %x1, 0
+ %2 = and i1 %1, %0
+ ret i1 %2
+}
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D132463.454792.patch
Type: text/x-patch
Size: 2057 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220823/f9563f91/attachment.bin>
More information about the llvm-commits
mailing list