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[InstCombine] add more tests for potentially poisonous shifts; NFC 

llvm-svn: 336454
This commit is contained in:
Sanjay Patel 2018-07-06 17:44:57 +00:00
parent 038dbf3c24
commit 5739587735
1 changed files with 43 additions and 0 deletions
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43
llvm/test/Transforms/InstCombine/shuffle_select.ll
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@ -998,6 +998,49 @@ define <4 x i32> @lshr_2_vars(<4 x i32> %v0, <4 x i32> %v1) {
ret <4 x i32> %t3
}
define <4 x i32> @lshr_2_vars_exact(<4 x i32> %v0, <4 x i32> %v1) {
; CHECK-LABEL: @lshr_2_vars_exact(
; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <4 x i32> [[V0:%.*]], <4 x i32> [[V1:%.*]], <4 x i32> <i32 4, i32 5, i32 2, i32 7>
; CHECK-NEXT: [[T3:%.*]] = lshr exact <4 x i32> <i32 5, i32 6, i32 3, i32 8>, [[TMP1]]
; CHECK-NEXT: ret <4 x i32> [[T3]]
;
%t1 = lshr exact <4 x i32> <i32 1, i32 2, i32 3, i32 4>, %v0
%t2 = lshr exact <4 x i32> <i32 5, i32 6, i32 7, i32 8>, %v1
%t3 = shufflevector <4 x i32> %t1, <4 x i32> %t2, <4 x i32> <i32 4, i32 5, i32 2, i32 7>
ret <4 x i32> %t3
}
; FIXME: This is not safe for the same reason that div/rem with undef mask is not safe.
; Analysis could determine that the shift has an undef shift amount creating poison.
define <4 x i32> @lshr_2_vars_undef_mask_elt(<4 x i32> %v0, <4 x i32> %v1) {
; CHECK-LABEL: @lshr_2_vars_undef_mask_elt(
; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <4 x i32> [[V0:%.*]], <4 x i32> [[V1:%.*]], <4 x i32> <i32 undef, i32 5, i32 2, i32 7>
; CHECK-NEXT: [[T3:%.*]] = lshr <4 x i32> <i32 undef, i32 6, i32 3, i32 8>, [[TMP1]]
; CHECK-NEXT: ret <4 x i32> [[T3]]
;
%t1 = lshr <4 x i32> <i32 1, i32 2, i32 3, i32 4>, %v0
%t2 = lshr <4 x i32> <i32 5, i32 6, i32 7, i32 8>, %v1
%t3 = shufflevector <4 x i32> %t1, <4 x i32> %t2, <4 x i32> <i32 undef, i32 5, i32 2, i32 7>
ret <4 x i32> %t3
}
; FIXME: This is not safe for the same reason that div/rem with undef mask is not safe.
; Analysis could determine that the shift has an undef shift amount creating poison.
; The 'exact' could also result in poison by choosing a -1 shift value.
define <4 x i32> @lshr_2_vars_exact_undef_mask_elt(<4 x i32> %v0, <4 x i32> %v1) {
; CHECK-LABEL: @lshr_2_vars_exact_undef_mask_elt(
; CHECK-NEXT: [[TMP1:%.*]] = shufflevector <4 x i32> [[V0:%.*]], <4 x i32> [[V1:%.*]], <4 x i32> <i32 undef, i32 5, i32 2, i32 7>
; CHECK-NEXT: [[T3:%.*]] = lshr exact <4 x i32> <i32 undef, i32 6, i32 3, i32 8>, [[TMP1]]
; CHECK-NEXT: ret <4 x i32> [[T3]]
;
%t1 = lshr exact <4 x i32> <i32 1, i32 2, i32 3, i32 4>, %v0
%t2 = lshr exact <4 x i32> <i32 5, i32 6, i32 7, i32 8>, %v1
%t3 = shufflevector <4 x i32> %t1, <4 x i32> %t2, <4 x i32> <i32 undef, i32 5, i32 2, i32 7>
ret <4 x i32> %t3
}
; Try weird types.
define <3 x i32> @ashr_2_vars(<3 x i32> %v0, <3 x i32> %v1) {