[NFC][InstCombine] Shift amount reassociation: revisit flag preservation tests

llvm-svn: 364657
This commit is contained in:
Roman Lebedev 2019-06-28 16:36:53 +00:00
parent e1eb25ff3e
commit 3b4f086df4
1 changed files with 26 additions and 12 deletions
llvm/test/Transforms/InstCombine

View File

@ -108,13 +108,13 @@ define i32 @t6_shl(i32 %x, i32 %y) {
; CHECK-NEXT: [[T0:%.*]] = sub i32 32, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = shl nuw i32 [[X:%.*]], [[T0]]
; CHECK-NEXT: [[T2:%.*]] = add i32 [[Y]], -2
; CHECK-NEXT: [[T3:%.*]] = shl i32 [[T1]], [[T2]]
; CHECK-NEXT: [[T3:%.*]] = shl nsw i32 [[T1]], [[T2]]
; CHECK-NEXT: ret i32 [[T3]]
;
%t0 = sub i32 32, %y
%t1 = shl nuw i32 %x, %t0 ; while there, test that we don't propagate partial 'nuw' flag
%t2 = add i32 %y, -2
%t3 = shl i32 %t1, %t2
%t3 = shl nsw i32 %t1, %t2 ; while there, test that we don't propagate partial 'nsw' flag
ret i32 %t3
}
define i32 @t7_ashr(i32 %x, i32 %y) {
@ -133,8 +133,8 @@ define i32 @t7_ashr(i32 %x, i32 %y) {
}
; If the same flag is present on both shifts, it can be kept.
define i32 @t8_lshr_flag_preservation(i32 %x, i32 %y) {
; CHECK-LABEL: @t8_lshr_flag_preservation(
define i32 @t8_lshr_exact_flag_preservation(i32 %x, i32 %y) {
; CHECK-LABEL: @t8_lshr_exact_flag_preservation(
; CHECK-NEXT: [[T0:%.*]] = sub i32 32, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = lshr exact i32 [[X:%.*]], [[T0]]
; CHECK-NEXT: [[T2:%.*]] = add i32 [[Y]], -2
@ -147,8 +147,8 @@ define i32 @t8_lshr_flag_preservation(i32 %x, i32 %y) {
%t3 = lshr exact i32 %t1, %t2
ret i32 %t3
}
define i32 @t9_ashr_flag_preservation(i32 %x, i32 %y) {
; CHECK-LABEL: @t9_ashr_flag_preservation(
define i32 @t9_ashr_exact_flag_preservation(i32 %x, i32 %y) {
; CHECK-LABEL: @t9_ashr_exact_flag_preservation(
; CHECK-NEXT: [[T0:%.*]] = sub i32 32, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = ashr exact i32 [[X:%.*]], [[T0]]
; CHECK-NEXT: [[T2:%.*]] = add i32 [[Y]], -2
@ -161,8 +161,8 @@ define i32 @t9_ashr_flag_preservation(i32 %x, i32 %y) {
%t3 = ashr exact i32 %t1, %t2
ret i32 %t3
}
define i32 @t10_shl_flag_preservation(i32 %x, i32 %y) {
; CHECK-LABEL: @t10_shl_flag_preservation(
define i32 @t10_shl_nuw_flag_preservation(i32 %x, i32 %y) {
; CHECK-LABEL: @t10_shl_nuw_flag_preservation(
; CHECK-NEXT: [[T0:%.*]] = sub i32 32, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = shl nuw i32 [[X:%.*]], [[T0]]
; CHECK-NEXT: [[T2:%.*]] = add i32 [[Y]], -2
@ -175,14 +175,28 @@ define i32 @t10_shl_flag_preservation(i32 %x, i32 %y) {
%t3 = shl nuw nsw i32 %t1, %t2 ; only 'nuw' should be propagated.
ret i32 %t3
}
define i32 @t11_shl_nsw_flag_preservation(i32 %x, i32 %y) {
; CHECK-LABEL: @t11_shl_nsw_flag_preservation(
; CHECK-NEXT: [[T0:%.*]] = sub i32 32, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = shl nsw i32 [[X:%.*]], [[T0]]
; CHECK-NEXT: [[T2:%.*]] = add i32 [[Y]], -2
; CHECK-NEXT: [[T3:%.*]] = shl nuw nsw i32 [[T1]], [[T2]]
; CHECK-NEXT: ret i32 [[T3]]
;
%t0 = sub i32 32, %y
%t1 = shl nsw i32 %x, %t0
%t2 = add i32 %y, -2
%t3 = shl nsw nuw i32 %t1, %t2 ; only 'nuw' should be propagated.
ret i32 %t3
}
; No one-use tests since we will only produce a single instruction here.
; Negative tests
; Can't fold, total shift would be 32
define i32 @n11(i32 %x, i32 %y) {
; CHECK-LABEL: @n11(
define i32 @n12(i32 %x, i32 %y) {
; CHECK-LABEL: @n12(
; CHECK-NEXT: [[T0:%.*]] = sub i32 30, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = lshr i32 [[X:%.*]], [[T0]]
; CHECK-NEXT: [[T2:%.*]] = add i32 [[Y]], 2
@ -196,8 +210,8 @@ define i32 @n11(i32 %x, i32 %y) {
ret i32 %t3
}
; Can't fold, for second channel the shift would 32
define <2 x i32> @t12_vec(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @t12_vec(
define <2 x i32> @t13_vec(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @t13_vec(
; CHECK-NEXT: [[T0:%.*]] = sub <2 x i32> <i32 32, i32 30>, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = lshr <2 x i32> [[X:%.*]], [[T0]]
; CHECK-NEXT: [[T2:%.*]] = add <2 x i32> [[Y]], <i32 -2, i32 2>