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454315178c
This is the last step in getting constant pattern matchers to allow undef elements in constant vectors. I'm adding a dedicated m_ZeroInt() function and building m_Zero() from that. In most cases, calling code can be updated to use m_ZeroInt() directly when there's no need to match pointers, but I'm leaving that efficiency optimization as a follow-up step because it's not always clear when that's ok. There are just enough icmp folds in InstSimplify that can be used for integer or pointer types, that we probably still want a generic m_Zero() for those cases. Otherwise, we could eliminate it (and possibly add a m_NullPtr() as an alias for isa<ConstantPointerNull>()). We're conservatively returning a full zero vector (zeroinitializer) in InstSimplify/InstCombine on some of these folds (see diffs in InstSimplify), but I'm not sure if that's actually necessary in all cases. We may be able to propagate an undef lane instead. One test where this happens is marked with 'TODO'. llvm-svn: 330550
75 lines
2.0 KiB
LLVM
75 lines
2.0 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -instsimplify -S | FileCheck %s
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define i32 @negate_nuw(i32 %x) {
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; CHECK-LABEL: @negate_nuw(
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; CHECK-NEXT: ret i32 0
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;
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%neg = sub nuw i32 0, %x
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ret i32 %neg
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}
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define <2 x i32> @negate_nuw_vec(<2 x i32> %x) {
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; CHECK-LABEL: @negate_nuw_vec(
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; CHECK-NEXT: ret <2 x i32> zeroinitializer
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;
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%neg = sub nuw <2 x i32> zeroinitializer, %x
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ret <2 x i32> %neg
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}
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define <2 x i32> @negate_nuw_vec_undef_elt(<2 x i32> %x) {
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; CHECK-LABEL: @negate_nuw_vec_undef_elt(
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; CHECK-NEXT: ret <2 x i32> zeroinitializer
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;
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%neg = sub nuw <2 x i32> <i32 0, i32 undef>, %x
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ret <2 x i32> %neg
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}
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define i8 @negate_zero_or_minsigned_nsw(i8 %x) {
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; CHECK-LABEL: @negate_zero_or_minsigned_nsw(
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; CHECK-NEXT: ret i8 0
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;
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%signbit = and i8 %x, 128
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%neg = sub nsw i8 0, %signbit
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ret i8 %neg
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}
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define <2 x i8> @negate_zero_or_minsigned_nsw_vec(<2 x i8> %x) {
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; CHECK-LABEL: @negate_zero_or_minsigned_nsw_vec(
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; CHECK-NEXT: ret <2 x i8> zeroinitializer
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;
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%signbit = shl <2 x i8> %x, <i8 7, i8 7>
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%neg = sub nsw <2 x i8> zeroinitializer, %signbit
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ret <2 x i8> %neg
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}
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define <2 x i8> @negate_zero_or_minsigned_nsw_vec_undef_elt(<2 x i8> %x) {
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; CHECK-LABEL: @negate_zero_or_minsigned_nsw_vec_undef_elt(
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; CHECK-NEXT: ret <2 x i8> zeroinitializer
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;
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%signbit = shl <2 x i8> %x, <i8 7, i8 7>
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%neg = sub nsw <2 x i8> <i8 undef, i8 0>, %signbit
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ret <2 x i8> %neg
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}
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define i8 @negate_zero_or_minsigned(i8 %x) {
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; CHECK-LABEL: @negate_zero_or_minsigned(
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; CHECK-NEXT: [[SIGNBIT:%.*]] = shl i8 [[X:%.*]], 7
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; CHECK-NEXT: ret i8 [[SIGNBIT]]
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;
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%signbit = shl i8 %x, 7
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%neg = sub i8 0, %signbit
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ret i8 %neg
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}
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define <2 x i8> @negate_zero_or_minsigned_vec(<2 x i8> %x) {
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; CHECK-LABEL: @negate_zero_or_minsigned_vec(
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; CHECK-NEXT: [[SIGNBIT:%.*]] = and <2 x i8> [[X:%.*]], <i8 -128, i8 -128>
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; CHECK-NEXT: ret <2 x i8> [[SIGNBIT]]
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;
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%signbit = and <2 x i8> %x, <i8 128, i8 128>
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%neg = sub <2 x i8> zeroinitializer, %signbit
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ret <2 x i8> %neg
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}
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