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Revert "[InstCombine] Negator: -(X << C) --> X * (-1 << C)" 

Breaks codegen tests, will recommit later.

This reverts commit 8aeb2fe13a.
This commit is contained in:
Roman Lebedev 2020-08-05 03:19:38 +03:00
parent 8aeb2fe13a
commit ac70b37a00
No known key found for this signature in database
GPG Key ID: 083C3EBB4A1689E0
5 changed files with 32 additions and 40 deletions
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12
llvm/lib/Transforms/InstCombine/InstCombineNegator.cpp
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@ -324,16 +324,10 @@ LLVM_NODISCARD Value *Negator::visitImpl(Value *V, unsigned Depth) {
}
case Instruction::Shl: {
// `shl` is negatible if the first operand is negatible.
if (Value *NegOp0 = negate(I->getOperand(0), Depth + 1))
return Builder.CreateShl(NegOp0, I->getOperand(1), I->getName() + ".neg");
// Otherwise, `shl %x, C` can be interpreted as `mul %x, 1<<C`.
auto *Op1C = dyn_cast<Constant>(I->getOperand(1));
if (!Op1C) // Early return.
Value *NegOp0 = negate(I->getOperand(0), Depth + 1);
if (!NegOp0) // Early return.
return nullptr;
return Builder.CreateMul(
I->getOperand(0),
ConstantExpr::getShl(Constant::getAllOnesValue(Op1C->getType()), Op1C),
I->getName() + ".neg");
return Builder.CreateShl(NegOp0, I->getOperand(1), I->getName() + ".neg");
}
case Instruction::Or:
if (!haveNoCommonBitsSet(I->getOperand(0), I->getOperand(1), DL, &AC, I,

3
llvm/test/Transforms/InstCombine/icmp.ll
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@ -512,8 +512,7 @@ define i1 @test24(i64 %i) {
; unsigned overflow does not happen during offset computation
define i1 @test24_neg_offs(i32* %p, i64 %offs) {
; CHECK-LABEL: @test24_neg_offs(
; CHECK-NEXT: [[P1_IDX_NEG:%.*]] = mul i64 [[OFFS:%.*]], -4
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i64 [[P1_IDX_NEG]], 8
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i64 [[OFFS:%.*]], -2
; CHECK-NEXT: ret i1 [[CMP]]
;
%p1 = getelementptr inbounds i32, i32* %p, i64 %offs

10
llvm/test/Transforms/InstCombine/sub-gep.ll
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@ -58,8 +58,9 @@ define i32 @test_inbounds_nuw_trunc([0 x i32]* %base, i64 %idx) {
define i64 @test_inbounds_nuw_swapped([0 x i32]* %base, i64 %idx) {
; CHECK-LABEL: @test_inbounds_nuw_swapped(
; CHECK-NEXT: [[P2_IDX_NEG:%.*]] = mul i64 [[IDX:%.*]], -4
; CHECK-NEXT: ret i64 [[P2_IDX_NEG]]
; CHECK-NEXT: [[P2_IDX:%.*]] = shl nsw i64 [[IDX:%.*]], 2
; CHECK-NEXT: [[DIFF_NEG:%.*]] = sub i64 0, [[P2_IDX]]
; CHECK-NEXT: ret i64 [[DIFF_NEG]]
;
%p1 = getelementptr inbounds [0 x i32], [0 x i32]* %base, i64 0, i64 0
%p2 = getelementptr inbounds [0 x i32], [0 x i32]* %base, i64 0, i64 %idx
@ -72,9 +73,8 @@ define i64 @test_inbounds_nuw_swapped([0 x i32]* %base, i64 %idx) {
; The sub and shl here could be nuw, but this is harder to handle.
define i64 @test_inbounds_nuw_two_gep([0 x i32]* %base, i64 %idx, i64 %idx2) {
; CHECK-LABEL: @test_inbounds_nuw_two_gep(
; CHECK-NEXT: [[P1_IDX_NEG:%.*]] = mul i64 [[IDX:%.*]], -4
; CHECK-NEXT: [[P2_IDX_NEG_NEG:%.*]] = shl i64 [[IDX2:%.*]], 2
; CHECK-NEXT: [[DOTNEG:%.*]] = add i64 [[P2_IDX_NEG_NEG]], [[P1_IDX_NEG]]
; CHECK-NEXT: [[P1_IDX1_NEG:%.*]] = sub i64 [[IDX2:%.*]], [[IDX:%.*]]
; CHECK-NEXT: [[DOTNEG:%.*]] = shl i64 [[P1_IDX1_NEG]], 2
; CHECK-NEXT: ret i64 [[DOTNEG]]
;
%p1 = getelementptr inbounds [0 x i32], [0 x i32]* %base, i64 0, i64 %idx

4
llvm/test/Transforms/InstCombine/sub-of-negatible.ll
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@ -1076,8 +1076,8 @@ define i8 @negate_left_shift_by_constant(i8 %x, i8 %y, i8 %z, i8 %k) {
; CHECK-LABEL: @negate_left_shift_by_constant(
; CHECK-NEXT: [[T0:%.*]] = sub i8 [[K:%.*]], [[Z:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1_NEG:%.*]] = mul i8 [[T0]], -16
; CHECK-NEXT: [[T2:%.*]] = add i8 [[T1_NEG]], [[X:%.*]]
; CHECK-NEXT: [[T1:%.*]] = shl i8 [[T0]], 4
; CHECK-NEXT: [[T2:%.*]] = sub i8 [[X:%.*]], [[T1]]
; CHECK-NEXT: ret i8 [[T2]]
;
%t0 = sub i8 %k, %z

43
llvm/test/Transforms/InstCombine/sub.ll
View File

@ -506,8 +506,8 @@ define i64 @test24b(i8* %P, i64 %A){
define i64 @test25(i8* %P, i64 %A){
; CHECK-LABEL: @test25(
; CHECK-NEXT: [[B_IDX_NEG_NEG:%.*]] = shl i64 [[A:%.*]], 1
; CHECK-NEXT: [[DOTNEG:%.*]] = add i64 [[B_IDX_NEG_NEG]], -84
; CHECK-NEXT: [[B_IDX:%.*]] = shl nsw i64 [[A:%.*]], 1
; CHECK-NEXT: [[DOTNEG:%.*]] = add i64 [[B_IDX]], -84
; CHECK-NEXT: ret i64 [[DOTNEG]]
;
%B = getelementptr inbounds [42 x i16], [42 x i16]* @Arr, i64 0, i64 %A
@ -521,8 +521,8 @@ define i64 @test25(i8* %P, i64 %A){
define i16 @test25_as1(i8 addrspace(1)* %P, i64 %A) {
; CHECK-LABEL: @test25_as1(
; CHECK-NEXT: [[TMP1:%.*]] = trunc i64 [[A:%.*]] to i16
; CHECK-NEXT: [[B_IDX_NEG_NEG:%.*]] = shl i16 [[TMP1]], 1
; CHECK-NEXT: [[DOTNEG:%.*]] = add i16 [[B_IDX_NEG_NEG]], -84
; CHECK-NEXT: [[B_IDX:%.*]] = shl nsw i16 [[TMP1]], 1
; CHECK-NEXT: [[DOTNEG:%.*]] = add i16 [[B_IDX]], -84
; CHECK-NEXT: ret i16 [[DOTNEG]]
;
%B = getelementptr inbounds [42 x i16], [42 x i16] addrspace(1)* @Arr_as1, i64 0, i64 %A
@ -557,8 +557,9 @@ define i64 @test_neg_shl_sub_extra_use1(i64 %a, i64 %b, i64* %p) {
; CHECK-LABEL: @test_neg_shl_sub_extra_use1(
; CHECK-NEXT: [[SUB:%.*]] = sub i64 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: store i64 [[SUB]], i64* [[P:%.*]], align 8
; CHECK-NEXT: [[MUL_NEG:%.*]] = mul i64 [[SUB]], -4
; CHECK-NEXT: ret i64 [[MUL_NEG]]
; CHECK-NEXT: [[MUL:%.*]] = shl i64 [[SUB]], 2
; CHECK-NEXT: [[NEG:%.*]] = sub i64 0, [[MUL]]
; CHECK-NEXT: ret i64 [[NEG]]
;
%sub = sub i64 %a, %b
store i64 %sub, i64* %p
@ -839,10 +840,9 @@ define i64 @test29(i8* %foo, i64 %i, i64 %j) {
define i64 @test30(i8* %foo, i64 %i, i64 %j) {
; CHECK-LABEL: @test30(
; CHECK-NEXT: [[GEP1_IDX_NEG:%.*]] = mul i64 [[I:%.*]], -4
; CHECK-NEXT: [[TMP1:%.*]] = add i64 [[GEP1_IDX_NEG]], [[J:%.*]]
; CHECK-NEXT: [[DIFF_NEG:%.*]] = sub i64 0, [[TMP1]]
; CHECK-NEXT: ret i64 [[DIFF_NEG]]
; CHECK-NEXT: [[GEP1_IDX:%.*]] = shl nsw i64 [[I:%.*]], 2
; CHECK-NEXT: [[DOTNEG:%.*]] = sub i64 [[GEP1_IDX]], [[J:%.*]]
; CHECK-NEXT: ret i64 [[DOTNEG]]
;
%bit = bitcast i8* %foo to i32*
%gep1 = getelementptr inbounds i32, i32* %bit, i64 %i
@ -855,10 +855,9 @@ define i64 @test30(i8* %foo, i64 %i, i64 %j) {
define i16 @test30_as1(i8 addrspace(1)* %foo, i16 %i, i16 %j) {
; CHECK-LABEL: @test30_as1(
; CHECK-NEXT: [[GEP1_IDX_NEG:%.*]] = mul i16 [[I:%.*]], -4
; CHECK-NEXT: [[TMP1:%.*]] = add i16 [[GEP1_IDX_NEG]], [[J:%.*]]
; CHECK-NEXT: [[DIFF_NEG:%.*]] = sub i16 0, [[TMP1]]
; CHECK-NEXT: ret i16 [[DIFF_NEG]]
; CHECK-NEXT: [[GEP1_IDX:%.*]] = shl nsw i16 [[I:%.*]], 2
; CHECK-NEXT: [[DOTNEG:%.*]] = sub i16 [[GEP1_IDX]], [[J:%.*]]
; CHECK-NEXT: ret i16 [[DOTNEG]]
;
%bit = bitcast i8 addrspace(1)* %foo to i32 addrspace(1)*
%gep1 = getelementptr inbounds i32, i32 addrspace(1)* %bit, i16 %i
@ -1311,8 +1310,8 @@ define i64 @test61([100 x [100 x i8]]* %foo, i64 %i, i64 %j) {
define i32 @test62(i32 %A) {
; CHECK-LABEL: @test62(
; CHECK-NEXT: [[B_NEG:%.*]] = mul i32 [[A:%.*]], -2
; CHECK-NEXT: [[C:%.*]] = add i32 [[B_NEG]], 2
; CHECK-NEXT: [[B:%.*]] = shl i32 [[A:%.*]], 1
; CHECK-NEXT: [[C:%.*]] = sub i32 2, [[B]]
; CHECK-NEXT: ret i32 [[C]]
;
%B = sub i32 1, %A
@ -1322,8 +1321,8 @@ define i32 @test62(i32 %A) {
define <2 x i32> @test62vec(<2 x i32> %A) {
; CHECK-LABEL: @test62vec(
; CHECK-NEXT: [[B_NEG:%.*]] = mul <2 x i32> [[A:%.*]], <i32 -2, i32 -2>
; CHECK-NEXT: [[C:%.*]] = add <2 x i32> [[B_NEG]], <i32 2, i32 2>
; CHECK-NEXT: [[B:%.*]] = shl <2 x i32> [[A:%.*]], <i32 1, i32 1>
; CHECK-NEXT: [[C:%.*]] = sub <2 x i32> <i32 2, i32 2>, [[B]]
; CHECK-NEXT: ret <2 x i32> [[C]]
;
%B = sub <2 x i32> <i32 1, i32 1>, %A
@ -1333,8 +1332,8 @@ define <2 x i32> @test62vec(<2 x i32> %A) {
define i32 @test63(i32 %A) {
; CHECK-LABEL: @test63(
; CHECK-NEXT: [[B_NEG_NEG:%.*]] = shl i32 [[A:%.*]], 1
; CHECK-NEXT: ret i32 [[B_NEG_NEG]]
; CHECK-NEXT: [[B:%.*]] = shl i32 [[A:%.*]], 1
; CHECK-NEXT: ret i32 [[B]]
;
%B = sub i32 1, %A
%C = shl i32 %B, 1
@ -1344,8 +1343,8 @@ define i32 @test63(i32 %A) {
define <2 x i32> @test63vec(<2 x i32> %A) {
; CHECK-LABEL: @test63vec(
; CHECK-NEXT: [[B_NEG_NEG:%.*]] = shl <2 x i32> [[A:%.*]], <i32 1, i32 1>
; CHECK-NEXT: ret <2 x i32> [[B_NEG_NEG]]
; CHECK-NEXT: [[B:%.*]] = shl <2 x i32> [[A:%.*]], <i32 1, i32 1>
; CHECK-NEXT: ret <2 x i32> [[B]]
;
%B = sub <2 x i32> <i32 1, i32 1>, %A
%C = shl <2 x i32> %B, <i32 1, i32 1>