8360c42e25
A follow-up for r329011. This may be changed to produce @llvm.sub.with.overflow in a later patch, but for now just make things more consistent overall. A few observations stem from this: * There does not seem to be a similar one-instruction fold for uadd-overflow * I'm not sure we'll want to canonicalize `B u> A` as `usub.with.overflow`, so since the `icmp` here no longer refers to `sub`, reconstructing `usub.with.overflow` will be problematic, and will likely require standalone pass (similar to DivRemPairs). https://rise4fun.com/Alive/Zqs Name: (A - B) u> A --> B u> A %t0 = sub i8 %A, %B %r = icmp ugt i8 %t0, %A => %r = icmp ugt i8 %B, %A Name: (A - B) u<= A --> B u<= A %t0 = sub i8 %A, %B %r = icmp ule i8 %t0, %A => %r = icmp ule i8 %B, %A Name: C u< (C - D) --> C u< D %t0 = sub i8 %C, %D %r = icmp ult i8 %C, %t0 => %r = icmp ult i8 %C, %D Name: C u>= (C - D) --> C u>= D %t0 = sub i8 %C, %D %r = icmp uge i8 %C, %t0 => %r = icmp uge i8 %C, %D llvm-svn: 371101
156 lines
3.7 KiB
LLVM
156 lines
3.7 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt %s -instcombine -S | FileCheck %s
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; Fold
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; (%x - %y) u> %x
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; to
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; @llvm.sub.with.overflow(%x, %y) + extractvalue
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define i1 @t0_basic(i8 %x, i8 %y) {
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; CHECK-LABEL: @t0_basic(
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; CHECK-NEXT: [[R:%.*]] = icmp ugt i8 [[Y:%.*]], [[X:%.*]]
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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%r = icmp ugt i8 %t0, %x
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ret i1 %r
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}
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define <2 x i1> @t1_vec(<2 x i8> %x, <2 x i8> %y) {
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; CHECK-LABEL: @t1_vec(
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; CHECK-NEXT: [[R:%.*]] = icmp ugt <2 x i8> [[Y:%.*]], [[X:%.*]]
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; CHECK-NEXT: ret <2 x i1> [[R]]
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;
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%t0 = sub <2 x i8> %x, %y
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%r = icmp ugt <2 x i8> %t0, %x
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ret <2 x i1> %r
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}
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; Commutativity
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define i1 @t2_commutative(i8 %x, i8 %y) {
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; CHECK-LABEL: @t2_commutative(
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; CHECK-NEXT: [[R:%.*]] = icmp ugt i8 [[Y:%.*]], [[X:%.*]]
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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%r = icmp ult i8 %x, %t0 ; swapped
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ret i1 %r
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}
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; Extra-use tests
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declare void @use8(i8)
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define i1 @t3_extrause0(i8 %x, i8 %y) {
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; CHECK-LABEL: @t3_extrause0(
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; CHECK-NEXT: [[T0:%.*]] = sub i8 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: call void @use8(i8 [[T0]])
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; CHECK-NEXT: [[R:%.*]] = icmp ult i8 [[X]], [[Y]]
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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call void @use8(i8 %t0)
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%r = icmp ugt i8 %t0, %x
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ret i1 %r
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}
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; Negative tests
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define i1 @n4_not_commutative(i8 %x, i8 %y) {
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; CHECK-LABEL: @n4_not_commutative(
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; CHECK-NEXT: [[T0:%.*]] = sub i8 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp ugt i8 [[T0]], [[Y]]
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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%r = icmp ugt i8 %t0, %y ; can't check against %y.
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ret i1 %r
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}
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define i1 @n5_wrong_pred0(i8 %x, i8 %y) {
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; CHECK-LABEL: @n5_wrong_pred0(
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; CHECK-NEXT: [[T0:%.*]] = sub i8 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp uge i8 [[T0]], [[X]]
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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%r = icmp uge i8 %t0, %x
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ret i1 %r
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}
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define i1 @n6_wrong_pred1(i8 %x, i8 %y) {
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; CHECK-LABEL: @n6_wrong_pred1(
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; CHECK-NEXT: [[T0:%.*]] = sub i8 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp ult i8 [[T0]], [[X]]
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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%r = icmp ult i8 %t0, %x
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ret i1 %r
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}
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define i1 @n7_wrong_pred2(i8 %x, i8 %y) {
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; CHECK-LABEL: @n7_wrong_pred2(
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; CHECK-NEXT: [[R:%.*]] = icmp eq i8 [[Y:%.*]], 0
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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%r = icmp eq i8 %t0, %x
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ret i1 %r
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}
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define i1 @n8_wrong_pred3(i8 %x, i8 %y) {
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; CHECK-LABEL: @n8_wrong_pred3(
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; CHECK-NEXT: [[R:%.*]] = icmp ne i8 [[Y:%.*]], 0
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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%r = icmp ne i8 %t0, %x
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ret i1 %r
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}
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define i1 @n9_wrong_pred4(i8 %x, i8 %y) {
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; CHECK-LABEL: @n9_wrong_pred4(
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; CHECK-NEXT: [[T0:%.*]] = sub i8 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp slt i8 [[T0]], [[X]]
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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%r = icmp slt i8 %t0, %x
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ret i1 %r
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}
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define i1 @n10_wrong_pred5(i8 %x, i8 %y) {
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; CHECK-LABEL: @n10_wrong_pred5(
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; CHECK-NEXT: [[T0:%.*]] = sub i8 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp sle i8 [[T0]], [[X]]
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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%r = icmp sle i8 %t0, %x
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ret i1 %r
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}
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define i1 @n11_wrong_pred6(i8 %x, i8 %y) {
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; CHECK-LABEL: @n11_wrong_pred6(
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; CHECK-NEXT: [[T0:%.*]] = sub i8 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp sgt i8 [[T0]], [[X]]
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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%r = icmp sgt i8 %t0, %x
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ret i1 %r
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}
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define i1 @n12_wrong_pred7(i8 %x, i8 %y) {
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; CHECK-LABEL: @n12_wrong_pred7(
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; CHECK-NEXT: [[T0:%.*]] = sub i8 [[X:%.*]], [[Y:%.*]]
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; CHECK-NEXT: [[R:%.*]] = icmp sge i8 [[T0]], [[X]]
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; CHECK-NEXT: ret i1 [[R]]
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;
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%t0 = sub i8 %x, %y
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%r = icmp sge i8 %t0, %x
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ret i1 %r
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}
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