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Revert "[InstCombine] Negator: -(X << C) --> X * (-1 << C)"
Breaks codegen tests, will recommit later. This reverts commit 8aeb2fe.
1 parent 8aeb2fe commit ac70b37

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5 files changed

+32
-40
lines changed

5 files changed

+32
-40
lines changed

‎llvm/lib/Transforms/InstCombine/InstCombineNegator.cpp

Lines changed: 3 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -324,16 +324,10 @@ LLVM_NODISCARD Value *Negator::visitImpl(Value *V, unsigned Depth) {
324324
}
325325
case Instruction::Shl: {
326326
// `shl` is negatible if the first operand is negatible.
327-
if (Value *NegOp0 = negate(I->getOperand(0), Depth + 1))
328-
return Builder.CreateShl(NegOp0, I->getOperand(1), I->getName() + ".neg");
329-
// Otherwise, `shl %x, C` can be interpreted as `mul %x, 1<<C`.
330-
auto *Op1C = dyn_cast<Constant>(I->getOperand(1));
331-
if (!Op1C) // Early return.
327+
Value *NegOp0 = negate(I->getOperand(0), Depth + 1);
328+
if (!NegOp0) // Early return.
332329
return nullptr;
333-
return Builder.CreateMul(
334-
I->getOperand(0),
335-
ConstantExpr::getShl(Constant::getAllOnesValue(Op1C->getType()), Op1C),
336-
I->getName() + ".neg");
330+
return Builder.CreateShl(NegOp0, I->getOperand(1), I->getName() + ".neg");
337331
}
338332
case Instruction::Or:
339333
if (!haveNoCommonBitsSet(I->getOperand(0), I->getOperand(1), DL, &AC, I,

‎llvm/test/Transforms/InstCombine/icmp.ll

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -512,8 +512,7 @@ define i1 @test24(i64 %i) {
512512
; unsigned overflow does not happen during offset computation
513513
define i1 @test24_neg_offs(i32* %p, i64 %offs) {
514514
; CHECK-LABEL: @test24_neg_offs(
515-
; CHECK-NEXT: [[P1_IDX_NEG:%.*]] = mul i64 [[OFFS:%.*]], -4
516-
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i64 [[P1_IDX_NEG]], 8
515+
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i64 [[OFFS:%.*]], -2
517516
; CHECK-NEXT: ret i1 [[CMP]]
518517
;
519518
%p1 = getelementptr inbounds i32, i32* %p, i64 %offs

‎llvm/test/Transforms/InstCombine/sub-gep.ll

Lines changed: 5 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -58,8 +58,9 @@ define i32 @test_inbounds_nuw_trunc([0 x i32]* %base, i64 %idx) {
5858

5959
define i64 @test_inbounds_nuw_swapped([0 x i32]* %base, i64 %idx) {
6060
; CHECK-LABEL: @test_inbounds_nuw_swapped(
61-
; CHECK-NEXT: [[P2_IDX_NEG:%.*]] = mul i64 [[IDX:%.*]], -4
62-
; CHECK-NEXT: ret i64 [[P2_IDX_NEG]]
61+
; CHECK-NEXT: [[P2_IDX:%.*]] = shl nsw i64 [[IDX:%.*]], 2
62+
; CHECK-NEXT: [[DIFF_NEG:%.*]] = sub i64 0, [[P2_IDX]]
63+
; CHECK-NEXT: ret i64 [[DIFF_NEG]]
6364
;
6465
%p1 = getelementptr inbounds [0 x i32], [0 x i32]* %base, i64 0, i64 0
6566
%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) {
7273
; The sub and shl here could be nuw, but this is harder to handle.
7374
define i64 @test_inbounds_nuw_two_gep([0 x i32]* %base, i64 %idx, i64 %idx2) {
7475
; CHECK-LABEL: @test_inbounds_nuw_two_gep(
75-
; CHECK-NEXT: [[P1_IDX_NEG:%.*]] = mul i64 [[IDX:%.*]], -4
76-
; CHECK-NEXT: [[P2_IDX_NEG_NEG:%.*]] = shl i64 [[IDX2:%.*]], 2
77-
; CHECK-NEXT: [[DOTNEG:%.*]] = add i64 [[P2_IDX_NEG_NEG]], [[P1_IDX_NEG]]
76+
; CHECK-NEXT: [[P1_IDX1_NEG:%.*]] = sub i64 [[IDX2:%.*]], [[IDX:%.*]]
77+
; CHECK-NEXT: [[DOTNEG:%.*]] = shl i64 [[P1_IDX1_NEG]], 2
7878
; CHECK-NEXT: ret i64 [[DOTNEG]]
7979
;
8080
%p1 = getelementptr inbounds [0 x i32], [0 x i32]* %base, i64 0, i64 %idx

‎llvm/test/Transforms/InstCombine/sub-of-negatible.ll

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1076,8 +1076,8 @@ define i8 @negate_left_shift_by_constant(i8 %x, i8 %y, i8 %z, i8 %k) {
10761076
; CHECK-LABEL: @negate_left_shift_by_constant(
10771077
; CHECK-NEXT: [[T0:%.*]] = sub i8 [[K:%.*]], [[Z:%.*]]
10781078
; CHECK-NEXT: call void @use8(i8 [[T0]])
1079-
; CHECK-NEXT: [[T1_NEG:%.*]] = mul i8 [[T0]], -16
1080-
; CHECK-NEXT: [[T2:%.*]] = add i8 [[T1_NEG]], [[X:%.*]]
1079+
; CHECK-NEXT: [[T1:%.*]] = shl i8 [[T0]], 4
1080+
; CHECK-NEXT: [[T2:%.*]] = sub i8 [[X:%.*]], [[T1]]
10811081
; CHECK-NEXT: ret i8 [[T2]]
10821082
;
10831083
%t0 = sub i8 %k, %z

‎llvm/test/Transforms/InstCombine/sub.ll

Lines changed: 21 additions & 22 deletions
Original file line numberDiff line numberDiff line change
@@ -506,8 +506,8 @@ define i64 @test24b(i8* %P, i64 %A){
506506

507507
define i64 @test25(i8* %P, i64 %A){
508508
; CHECK-LABEL: @test25(
509-
; CHECK-NEXT: [[B_IDX_NEG_NEG:%.*]] = shl i64 [[A:%.*]], 1
510-
; CHECK-NEXT: [[DOTNEG:%.*]] = add i64 [[B_IDX_NEG_NEG]], -84
509+
; CHECK-NEXT: [[B_IDX:%.*]] = shl nsw i64 [[A:%.*]], 1
510+
; CHECK-NEXT: [[DOTNEG:%.*]] = add i64 [[B_IDX]], -84
511511
; CHECK-NEXT: ret i64 [[DOTNEG]]
512512
;
513513
%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){
521521
define i16 @test25_as1(i8 addrspace(1)* %P, i64 %A) {
522522
; CHECK-LABEL: @test25_as1(
523523
; CHECK-NEXT: [[TMP1:%.*]] = trunc i64 [[A:%.*]] to i16
524-
; CHECK-NEXT: [[B_IDX_NEG_NEG:%.*]] = shl i16 [[TMP1]], 1
525-
; CHECK-NEXT: [[DOTNEG:%.*]] = add i16 [[B_IDX_NEG_NEG]], -84
524+
; CHECK-NEXT: [[B_IDX:%.*]] = shl nsw i16 [[TMP1]], 1
525+
; CHECK-NEXT: [[DOTNEG:%.*]] = add i16 [[B_IDX]], -84
526526
; CHECK-NEXT: ret i16 [[DOTNEG]]
527527
;
528528
%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) {
557557
; CHECK-LABEL: @test_neg_shl_sub_extra_use1(
558558
; CHECK-NEXT: [[SUB:%.*]] = sub i64 [[A:%.*]], [[B:%.*]]
559559
; CHECK-NEXT: store i64 [[SUB]], i64* [[P:%.*]], align 8
560-
; CHECK-NEXT: [[MUL_NEG:%.*]] = mul i64 [[SUB]], -4
561-
; CHECK-NEXT: ret i64 [[MUL_NEG]]
560+
; CHECK-NEXT: [[MUL:%.*]] = shl i64 [[SUB]], 2
561+
; CHECK-NEXT: [[NEG:%.*]] = sub i64 0, [[MUL]]
562+
; CHECK-NEXT: ret i64 [[NEG]]
562563
;
563564
%sub = sub i64 %a, %b
564565
store i64 %sub, i64* %p
@@ -839,10 +840,9 @@ define i64 @test29(i8* %foo, i64 %i, i64 %j) {
839840

840841
define i64 @test30(i8* %foo, i64 %i, i64 %j) {
841842
; CHECK-LABEL: @test30(
842-
; CHECK-NEXT: [[GEP1_IDX_NEG:%.*]] = mul i64 [[I:%.*]], -4
843-
; CHECK-NEXT: [[TMP1:%.*]] = add i64 [[GEP1_IDX_NEG]], [[J:%.*]]
844-
; CHECK-NEXT: [[DIFF_NEG:%.*]] = sub i64 0, [[TMP1]]
845-
; CHECK-NEXT: ret i64 [[DIFF_NEG]]
843+
; CHECK-NEXT: [[GEP1_IDX:%.*]] = shl nsw i64 [[I:%.*]], 2
844+
; CHECK-NEXT: [[DOTNEG:%.*]] = sub i64 [[GEP1_IDX]], [[J:%.*]]
845+
; CHECK-NEXT: ret i64 [[DOTNEG]]
846846
;
847847
%bit = bitcast i8* %foo to i32*
848848
%gep1 = getelementptr inbounds i32, i32* %bit, i64 %i
@@ -855,10 +855,9 @@ define i64 @test30(i8* %foo, i64 %i, i64 %j) {
855855

856856
define i16 @test30_as1(i8 addrspace(1)* %foo, i16 %i, i16 %j) {
857857
; CHECK-LABEL: @test30_as1(
858-
; CHECK-NEXT: [[GEP1_IDX_NEG:%.*]] = mul i16 [[I:%.*]], -4
859-
; CHECK-NEXT: [[TMP1:%.*]] = add i16 [[GEP1_IDX_NEG]], [[J:%.*]]
860-
; CHECK-NEXT: [[DIFF_NEG:%.*]] = sub i16 0, [[TMP1]]
861-
; CHECK-NEXT: ret i16 [[DIFF_NEG]]
858+
; CHECK-NEXT: [[GEP1_IDX:%.*]] = shl nsw i16 [[I:%.*]], 2
859+
; CHECK-NEXT: [[DOTNEG:%.*]] = sub i16 [[GEP1_IDX]], [[J:%.*]]
860+
; CHECK-NEXT: ret i16 [[DOTNEG]]
862861
;
863862
%bit = bitcast i8 addrspace(1)* %foo to i32 addrspace(1)*
864863
%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) {
13111310

13121311
define i32 @test62(i32 %A) {
13131312
; CHECK-LABEL: @test62(
1314-
; CHECK-NEXT: [[B_NEG:%.*]] = mul i32 [[A:%.*]], -2
1315-
; CHECK-NEXT: [[C:%.*]] = add i32 [[B_NEG]], 2
1313+
; CHECK-NEXT: [[B:%.*]] = shl i32 [[A:%.*]], 1
1314+
; CHECK-NEXT: [[C:%.*]] = sub i32 2, [[B]]
13161315
; CHECK-NEXT: ret i32 [[C]]
13171316
;
13181317
%B = sub i32 1, %A
@@ -1322,8 +1321,8 @@ define i32 @test62(i32 %A) {
13221321

13231322
define <2 x i32> @test62vec(<2 x i32> %A) {
13241323
; CHECK-LABEL: @test62vec(
1325-
; CHECK-NEXT: [[B_NEG:%.*]] = mul <2 x i32> [[A:%.*]], <i32 -2, i32 -2>
1326-
; CHECK-NEXT: [[C:%.*]] = add <2 x i32> [[B_NEG]], <i32 2, i32 2>
1324+
; CHECK-NEXT: [[B:%.*]] = shl <2 x i32> [[A:%.*]], <i32 1, i32 1>
1325+
; CHECK-NEXT: [[C:%.*]] = sub <2 x i32> <i32 2, i32 2>, [[B]]
13271326
; CHECK-NEXT: ret <2 x i32> [[C]]
13281327
;
13291328
%B = sub <2 x i32> <i32 1, i32 1>, %A
@@ -1333,8 +1332,8 @@ define <2 x i32> @test62vec(<2 x i32> %A) {
13331332

13341333
define i32 @test63(i32 %A) {
13351334
; CHECK-LABEL: @test63(
1336-
; CHECK-NEXT: [[B_NEG_NEG:%.*]] = shl i32 [[A:%.*]], 1
1337-
; CHECK-NEXT: ret i32 [[B_NEG_NEG]]
1335+
; CHECK-NEXT: [[B:%.*]] = shl i32 [[A:%.*]], 1
1336+
; CHECK-NEXT: ret i32 [[B]]
13381337
;
13391338
%B = sub i32 1, %A
13401339
%C = shl i32 %B, 1
@@ -1344,8 +1343,8 @@ define i32 @test63(i32 %A) {
13441343

13451344
define <2 x i32> @test63vec(<2 x i32> %A) {
13461345
; CHECK-LABEL: @test63vec(
1347-
; CHECK-NEXT: [[B_NEG_NEG:%.*]] = shl <2 x i32> [[A:%.*]], <i32 1, i32 1>
1348-
; CHECK-NEXT: ret <2 x i32> [[B_NEG_NEG]]
1346+
; CHECK-NEXT: [[B:%.*]] = shl <2 x i32> [[A:%.*]], <i32 1, i32 1>
1347+
; CHECK-NEXT: ret <2 x i32> [[B]]
13491348
;
13501349
%B = sub <2 x i32> <i32 1, i32 1>, %A
13511350
%C = shl <2 x i32> %B, <i32 1, i32 1>

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