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[X86] Improve 64-bit shifts on 32-bit targets (PR14593)
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As discussed on PR14593, this patch adds support for lowering to SHLD/SHRD from the patterns generated by DAGTypeLegalizer::ExpandShiftWithKnownAmountBit.

Differential Revision: https://reviews.llvm.org/D23000

llvm-svn: 277299
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@RKSimon
RKSimon committed Jul 31, 2016
1 parent 6004952 commit 6be48e4
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Showing 4 changed files with 72 additions and 127 deletions.
34 changes: 30 additions & 4 deletions llvm/lib/Target/X86/X86ISelLowering.cpp
View file
Expand Up @@ -28631,18 +28631,23 @@ static SDValue combineOr(SDNode *N, SelectionDAG &DAG,
unsigned Opc = X86ISD::SHLD;
SDValue Op0 = N0.getOperand(0);
SDValue Op1 = N1.getOperand(0);
if (ShAmt0.getOpcode() == ISD::SUB) {
if (ShAmt0.getOpcode() == ISD::SUB ||
ShAmt0.getOpcode() == ISD::XOR) {
Opc = X86ISD::SHRD;
std::swap(Op0, Op1);
std::swap(ShAmt0, ShAmt1);
}

// OR( SHL( X, C ), SRL( Y, 32 - C ) ) -> SHLD( X, Y, C )
// OR( SRL( X, C ), SHL( Y, 32 - C ) ) -> SHRD( X, Y, C )
// OR( SHL( X, C ), SRL( SRL( Y, 1 ), XOR( C, 31 ) ) ) -> SHLD( X, Y, C )
// OR( SRL( X, C ), SHL( SHL( Y, 1 ), XOR( C, 31 ) ) ) -> SHRD( X, Y, C )
unsigned Bits = VT.getSizeInBits();
if (ShAmt1.getOpcode() == ISD::SUB) {
SDValue Sum = ShAmt1.getOperand(0);
if (ConstantSDNode *SumC = dyn_cast<ConstantSDNode>(Sum)) {
SDValue ShAmt1Op1 = ShAmt1.getOperand(1);
if (ShAmt1Op1.getNode()->getOpcode() == ISD::TRUNCATE)
if (ShAmt1Op1.getOpcode() == ISD::TRUNCATE)
ShAmt1Op1 = ShAmt1Op1.getOperand(0);
if (SumC->getSExtValue() == Bits && ShAmt1Op1 == ShAmt0)
return DAG.getNode(Opc, DL, VT,
Expand All @@ -28652,12 +28657,33 @@ static SDValue combineOr(SDNode *N, SelectionDAG &DAG,
}
} else if (ConstantSDNode *ShAmt1C = dyn_cast<ConstantSDNode>(ShAmt1)) {
ConstantSDNode *ShAmt0C = dyn_cast<ConstantSDNode>(ShAmt0);
if (ShAmt0C &&
ShAmt0C->getSExtValue() + ShAmt1C->getSExtValue() == Bits)
if (ShAmt0C && (ShAmt0C->getSExtValue() + ShAmt1C->getSExtValue()) == Bits)
return DAG.getNode(Opc, DL, VT,
N0.getOperand(0), N1.getOperand(0),
DAG.getNode(ISD::TRUNCATE, DL,
MVT::i8, ShAmt0));
} else if (ShAmt1.getOpcode() == ISD::XOR) {
SDValue Mask = ShAmt1.getOperand(1);
if (ConstantSDNode *MaskC = dyn_cast<ConstantSDNode>(Mask)) {
unsigned InnerShift = (X86ISD::SHLD == Opc ? ISD::SRL : ISD::SHL);
SDValue ShAmt1Op0 = ShAmt1.getOperand(0);
if (ShAmt1Op0.getOpcode() == ISD::TRUNCATE)
ShAmt1Op0 = ShAmt1Op0.getOperand(0);
if (MaskC->getSExtValue() == (Bits - 1) && ShAmt1Op0 == ShAmt0) {
if (Op1.getOpcode() == InnerShift &&
isa<ConstantSDNode>(Op1.getOperand(1)) &&
Op1.getConstantOperandVal(1) == 1) {
return DAG.getNode(Opc, DL, VT, Op0, Op1.getOperand(0),
DAG.getNode(ISD::TRUNCATE, DL, MVT::i8, ShAmt0));
}
// Test for ADD( Y, Y ) as an equivalent to SHL( Y, 1 ).
if (InnerShift == ISD::SHL && Op1.getOpcode() == ISD::ADD &&
Op1.getOperand(0) == Op1.getOperand(1)) {
return DAG.getNode(Opc, DL, VT, Op0, Op1.getOperand(0),
DAG.getNode(ISD::TRUNCATE, DL, MVT::i8, ShAmt0));
}
}
}
}

return SDValue();
Expand Down
48 changes: 13 additions & 35 deletions llvm/test/CodeGen/X86/legalize-shift-64.ll
View file
Expand Up @@ -24,19 +24,13 @@ define i64 @test2(i64 %xx, i32 %test) nounwind {
; CHECK-LABEL: test2:
; CHECK: # BB#0:
; CHECK-NEXT: pushl %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %esi
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %ch
; CHECK-NEXT: andb $7, %ch
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: shll %cl, %esi
; CHECK-NEXT: movl %eax, %edx
; CHECK-NEXT: shrl %edx
; CHECK-NEXT: xorb $31, %cl
; CHECK-NEXT: shrl %cl, %edx
; CHECK-NEXT: orl %esi, %edx
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %edx
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %cl
; CHECK-NEXT: andb $7, %cl
; CHECK-NEXT: movl %esi, %eax
; CHECK-NEXT: shll %cl, %eax
; CHECK-NEXT: shldl %cl, %esi, %edx
; CHECK-NEXT: popl %esi
; CHECK-NEXT: retl
%and = and i32 %test, 7
Expand All @@ -48,20 +42,12 @@ define i64 @test2(i64 %xx, i32 %test) nounwind {
define i64 @test3(i64 %xx, i32 %test) nounwind {
; CHECK-LABEL: test3:
; CHECK: # BB#0:
; CHECK-NEXT: pushl %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %edx
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %ch
; CHECK-NEXT: andb $7, %ch
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: shrl %cl, %esi
; CHECK-NEXT: leal (%edx,%edx), %eax
; CHECK-NEXT: xorb $31, %cl
; CHECK-NEXT: shll %cl, %eax
; CHECK-NEXT: orl %esi, %eax
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %cl
; CHECK-NEXT: andb $7, %cl
; CHECK-NEXT: shrdl %cl, %edx, %eax
; CHECK-NEXT: shrl %cl, %edx
; CHECK-NEXT: popl %esi
; CHECK-NEXT: retl
%and = and i32 %test, 7
%sh_prom = zext i32 %and to i64
Expand All @@ -72,20 +58,12 @@ define i64 @test3(i64 %xx, i32 %test) nounwind {
define i64 @test4(i64 %xx, i32 %test) nounwind {
; CHECK-LABEL: test4:
; CHECK: # BB#0:
; CHECK-NEXT: pushl %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %edx
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %ch
; CHECK-NEXT: andb $7, %ch
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: shrl %cl, %esi
; CHECK-NEXT: leal (%edx,%edx), %eax
; CHECK-NEXT: xorb $31, %cl
; CHECK-NEXT: shll %cl, %eax
; CHECK-NEXT: orl %esi, %eax
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %cl
; CHECK-NEXT: andb $7, %cl
; CHECK-NEXT: shrdl %cl, %edx, %eax
; CHECK-NEXT: sarl %cl, %edx
; CHECK-NEXT: popl %esi
; CHECK-NEXT: retl
%and = and i32 %test, 7
%sh_prom = zext i32 %and to i64
Expand Down
26 changes: 5 additions & 21 deletions llvm/test/CodeGen/X86/shift-double-x86_64.ll
View file
Expand Up @@ -67,13 +67,7 @@ define i64 @test5(i64 %hi, i64 %lo, i64 %bits) nounwind {
; CHECK-LABEL: test5:
; CHECK: # BB#0:
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: xorl $63, %ecx
; CHECK-NEXT: shrq %rsi
; CHECK-NEXT: # kill: %CL<def> %CL<kill> %ECX<kill>
; CHECK-NEXT: shrq %cl, %rsi
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: shlq %cl, %rdi
; CHECK-NEXT: orq %rsi, %rdi
; CHECK-NEXT: shldq %cl, %rsi, %rdi
; CHECK-NEXT: movq %rdi, %rax
; CHECK-NEXT: retq
%bits64 = xor i64 %bits, 63
Expand All @@ -88,13 +82,8 @@ define i64 @test6(i64 %hi, i64 %lo, i64 %bits) nounwind {
; CHECK-LABEL: test6:
; CHECK: # BB#0:
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: xorl $63, %ecx
; CHECK-NEXT: leaq (%rsi,%rsi), %rax
; CHECK-NEXT: # kill: %CL<def> %CL<kill> %ECX<kill>
; CHECK-NEXT: shlq %cl, %rax
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: shrq %cl, %rdi
; CHECK-NEXT: orq %rdi, %rax
; CHECK-NEXT: shrdq %cl, %rsi, %rdi
; CHECK-NEXT: movq %rdi, %rax
; CHECK-NEXT: retq
%bits64 = xor i64 %bits, 63
%lo2 = shl i64 %lo, 1
Expand All @@ -108,13 +97,8 @@ define i64 @test7(i64 %hi, i64 %lo, i64 %bits) nounwind {
; CHECK-LABEL: test7:
; CHECK: # BB#0:
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: xorl $63, %ecx
; CHECK-NEXT: leaq (%rsi,%rsi), %rax
; CHECK-NEXT: # kill: %CL<def> %CL<kill> %ECX<kill>
; CHECK-NEXT: shlq %cl, %rax
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: shrq %cl, %rdi
; CHECK-NEXT: orq %rdi, %rax
; CHECK-NEXT: shrdq %cl, %rsi, %rdi
; CHECK-NEXT: movq %rdi, %rax
; CHECK-NEXT: retq
%bits64 = xor i64 %bits, 63
%lo2 = add i64 %lo, %lo
Expand Down
91 changes: 24 additions & 67 deletions llvm/test/CodeGen/X86/shift-double.ll
View file
Expand Up @@ -151,19 +151,13 @@ define i64 @test8(i64 %val, i32 %bits) nounwind {
; CHECK-LABEL: test8:
; CHECK: # BB#0:
; CHECK-NEXT: pushl %esi
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %ch
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %cl
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %esi
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: shll %cl, %esi
; CHECK-NEXT: movl %eax, %edx
; CHECK-NEXT: shrl %edx
; CHECK-NEXT: andb $31, %cl
; CHECK-NEXT: xorb $31, %cl
; CHECK-NEXT: shrl %cl, %edx
; CHECK-NEXT: orl %esi, %edx
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %edx
; CHECK-NEXT: movl %esi, %eax
; CHECK-NEXT: shll %cl, %eax
; CHECK-NEXT: andb $31, %cl
; CHECK-NEXT: shldl %cl, %esi, %edx
; CHECK-NEXT: popl %esi
; CHECK-NEXT: retl
%and = and i32 %bits, 31
Expand All @@ -176,18 +170,13 @@ define i64 @test9(i64 %val, i32 %bits) nounwind {
; CHECK-LABEL: test9:
; CHECK: # BB#0:
; CHECK-NEXT: pushl %esi
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %ch
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %cl
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %edx
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: shrl %cl, %esi
; CHECK-NEXT: leal (%edx,%edx), %eax
; CHECK-NEXT: andb $31, %cl
; CHECK-NEXT: xorb $31, %cl
; CHECK-NEXT: shll %cl, %eax
; CHECK-NEXT: orl %esi, %eax
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: movl %esi, %edx
; CHECK-NEXT: sarl %cl, %edx
; CHECK-NEXT: andb $31, %cl
; CHECK-NEXT: shrdl %cl, %esi, %eax
; CHECK-NEXT: popl %esi
; CHECK-NEXT: retl
%and = and i32 %bits, 31
Expand All @@ -200,18 +189,13 @@ define i64 @test10(i64 %val, i32 %bits) nounwind {
; CHECK-LABEL: test10:
; CHECK: # BB#0:
; CHECK-NEXT: pushl %esi
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %ch
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %cl
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %edx
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: shrl %cl, %esi
; CHECK-NEXT: leal (%edx,%edx), %eax
; CHECK-NEXT: andb $31, %cl
; CHECK-NEXT: xorb $31, %cl
; CHECK-NEXT: shll %cl, %eax
; CHECK-NEXT: orl %esi, %eax
; CHECK-NEXT: movb %ch, %cl
; CHECK-NEXT: movl %esi, %edx
; CHECK-NEXT: shrl %cl, %edx
; CHECK-NEXT: andb $31, %cl
; CHECK-NEXT: shrdl %cl, %esi, %eax
; CHECK-NEXT: popl %esi
; CHECK-NEXT: retl
%and = and i32 %bits, 31
Expand Down Expand Up @@ -291,19 +275,10 @@ define i32 @test14(i32 %hi, i32 %lo, i32 %bits) nounwind {
define i32 @test15(i32 %hi, i32 %lo, i32 %bits) nounwind {
; CHECK-LABEL: test15:
; CHECK: # BB#0:
; CHECK-NEXT: pushl %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %esi
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %cl
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %edx
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: xorl $31, %ecx
; CHECK-NEXT: shrl %esi
; CHECK-NEXT: # kill: %CL<def> %CL<kill> %ECX<kill>
; CHECK-NEXT: shrl %cl, %esi
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: shll %cl, %eax
; CHECK-NEXT: orl %esi, %eax
; CHECK-NEXT: popl %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: shldl %cl, %edx, %eax
; CHECK-NEXT: retl
%bits32 = xor i32 %bits, 31
%lo2 = lshr i32 %lo, 1
Expand All @@ -316,19 +291,10 @@ define i32 @test15(i32 %hi, i32 %lo, i32 %bits) nounwind {
define i32 @test16(i32 %hi, i32 %lo, i32 %bits) nounwind {
; CHECK-LABEL: test16:
; CHECK: # BB#0:
; CHECK-NEXT: pushl %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %esi
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %cl
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %edx
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: xorl $31, %ecx
; CHECK-NEXT: addl %esi, %esi
; CHECK-NEXT: # kill: %CL<def> %CL<kill> %ECX<kill>
; CHECK-NEXT: shll %cl, %esi
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: shrl %cl, %eax
; CHECK-NEXT: orl %esi, %eax
; CHECK-NEXT: popl %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: shrdl %cl, %edx, %eax
; CHECK-NEXT: retl
%bits32 = xor i32 %bits, 31
%lo2 = shl i32 %lo, 1
Expand All @@ -341,19 +307,10 @@ define i32 @test16(i32 %hi, i32 %lo, i32 %bits) nounwind {
define i32 @test17(i32 %hi, i32 %lo, i32 %bits) nounwind {
; CHECK-LABEL: test17:
; CHECK: # BB#0:
; CHECK-NEXT: pushl %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %esi
; CHECK-NEXT: movb {{[0-9]+}}(%esp), %cl
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %edx
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: xorl $31, %ecx
; CHECK-NEXT: addl %esi, %esi
; CHECK-NEXT: # kill: %CL<def> %CL<kill> %ECX<kill>
; CHECK-NEXT: shll %cl, %esi
; CHECK-NEXT: movl %edx, %ecx
; CHECK-NEXT: shrl %cl, %eax
; CHECK-NEXT: orl %esi, %eax
; CHECK-NEXT: popl %esi
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: shrdl %cl, %edx, %eax
; CHECK-NEXT: retl
%bits32 = xor i32 %bits, 31
%lo2 = add i32 %lo, %lo
Expand Down

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