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[InstSimplify] fold shifts by sext bool 

https://rise4fun.com/Alive/c3Y

llvm-svn: 335633
This commit is contained in:
Sanjay Patel 2018-06-26 17:31:38 +00:00
parent 91433f6877
commit ad0bfb844d
2 changed files with 11 additions and 19 deletions
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6
llvm/lib/Analysis/InstructionSimplify.cpp
View File

@ -1162,7 +1162,11 @@ static Value *SimplifyShift(Instruction::BinaryOps Opcode, Value *Op0,
return Constant::getNullValue(Op0->getType()); return Constant::getNullValue(Op0->getType());
// X shift by 0 -> X // X shift by 0 -> X
if (match(Op1, m_Zero())) // Shift-by-sign-extended bool must be shift-by-0 because shift-by-all-ones
// would be poison.
Value *X;
if (match(Op1, m_Zero()) ||
(match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)))
return Op0; return Op0;
// Fold undefined shifts. // Fold undefined shifts.

24
llvm/test/Transforms/InstSimplify/shift.ll
View File

@ -123,9 +123,7 @@ define <3 x i8> @ashr_all_ones_vec_with_undef_elts(<3 x i8> %x, <3 x i8> %y) {
define i8 @lshr_by_sext_bool(i1 %x, i8 %y) { define i8 @lshr_by_sext_bool(i1 %x, i8 %y) {
; CHECK-LABEL: @lshr_by_sext_bool( ; CHECK-LABEL: @lshr_by_sext_bool(
; CHECK-NEXT: [[S:%.*]] = sext i1 [[X:%.*]] to i8 ; CHECK-NEXT: ret i8 [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = lshr i8 [[Y:%.*]], [[S]]
; CHECK-NEXT: ret i8 [[R]]
; ;
%s = sext i1 %x to i8 %s = sext i1 %x to i8
%r = lshr i8 %y, %s %r = lshr i8 %y, %s
@ -134,9 +132,7 @@ define i8 @lshr_by_sext_bool(i1 %x, i8 %y) {
define <2 x i8> @lshr_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) { define <2 x i8> @lshr_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) {
; CHECK-LABEL: @lshr_by_sext_bool_vec( ; CHECK-LABEL: @lshr_by_sext_bool_vec(
; CHECK-NEXT: [[S:%.*]] = sext <2 x i1> [[X:%.*]] to <2 x i8> ; CHECK-NEXT: ret <2 x i8> [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = lshr <2 x i8> [[Y:%.*]], [[S]]
; CHECK-NEXT: ret <2 x i8> [[R]]
; ;
%s = sext <2 x i1> %x to <2 x i8> %s = sext <2 x i1> %x to <2 x i8>
%r = lshr <2 x i8> %y, %s %r = lshr <2 x i8> %y, %s
@ -145,9 +141,7 @@ define <2 x i8> @lshr_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) {
define i8 @ashr_by_sext_bool(i1 %x, i8 %y) { define i8 @ashr_by_sext_bool(i1 %x, i8 %y) {
; CHECK-LABEL: @ashr_by_sext_bool( ; CHECK-LABEL: @ashr_by_sext_bool(
; CHECK-NEXT: [[S:%.*]] = sext i1 [[X:%.*]] to i8 ; CHECK-NEXT: ret i8 [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = ashr i8 [[Y:%.*]], [[S]]
; CHECK-NEXT: ret i8 [[R]]
; ;
%s = sext i1 %x to i8 %s = sext i1 %x to i8
%r = ashr i8 %y, %s %r = ashr i8 %y, %s
@ -156,9 +150,7 @@ define i8 @ashr_by_sext_bool(i1 %x, i8 %y) {
define <2 x i8> @ashr_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) { define <2 x i8> @ashr_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) {
; CHECK-LABEL: @ashr_by_sext_bool_vec( ; CHECK-LABEL: @ashr_by_sext_bool_vec(
; CHECK-NEXT: [[S:%.*]] = sext <2 x i1> [[X:%.*]] to <2 x i8> ; CHECK-NEXT: ret <2 x i8> [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = ashr <2 x i8> [[Y:%.*]], [[S]]
; CHECK-NEXT: ret <2 x i8> [[R]]
; ;
%s = sext <2 x i1> %x to <2 x i8> %s = sext <2 x i1> %x to <2 x i8>
%r = ashr <2 x i8> %y, %s %r = ashr <2 x i8> %y, %s
@ -167,9 +159,7 @@ define <2 x i8> @ashr_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) {
define i8 @shl_by_sext_bool(i1 %x, i8 %y) { define i8 @shl_by_sext_bool(i1 %x, i8 %y) {
; CHECK-LABEL: @shl_by_sext_bool( ; CHECK-LABEL: @shl_by_sext_bool(
; CHECK-NEXT: [[S:%.*]] = sext i1 [[X:%.*]] to i8 ; CHECK-NEXT: ret i8 [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = shl i8 [[Y:%.*]], [[S]]
; CHECK-NEXT: ret i8 [[R]]
; ;
%s = sext i1 %x to i8 %s = sext i1 %x to i8
%r = shl i8 %y, %s %r = shl i8 %y, %s
@ -178,9 +168,7 @@ define i8 @shl_by_sext_bool(i1 %x, i8 %y) {
define <2 x i8> @shl_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) { define <2 x i8> @shl_by_sext_bool_vec(<2 x i1> %x, <2 x i8> %y) {
; CHECK-LABEL: @shl_by_sext_bool_vec( ; CHECK-LABEL: @shl_by_sext_bool_vec(
; CHECK-NEXT: [[S:%.*]] = sext <2 x i1> [[X:%.*]] to <2 x i8> ; CHECK-NEXT: ret <2 x i8> [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = shl <2 x i8> [[Y:%.*]], [[S]]
; CHECK-NEXT: ret <2 x i8> [[R]]
; ;
%s = sext <2 x i1> %x to <2 x i8> %s = sext <2 x i1> %x to <2 x i8>
%r = shl <2 x i8> %y, %s %r = shl <2 x i8> %y, %s