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[Sparc]: correct the 'set' synthetic instruction
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Differential Revision: http://reviews.llvm.org/D12194

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245575 91177308-0d34-0410-b5e6-96231b3b80d8
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@snuglas
snuglas committed Aug 20, 2015
1 parent b2026a6 commit 950d9fd
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Showing 3 changed files with 115 additions and 7 deletions.
42 changes: 37 additions & 5 deletions lib/Target/Sparc/AsmParser/SparcAsmParser.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -437,7 +437,22 @@ void SparcAsmParser::expandSET(MCInst &Inst, SMLoc IDLoc,

// the imm operand can be either an expression or an immediate.
bool IsImm = Inst.getOperand(1).isImm();
uint64_t ImmValue = IsImm ? MCValOp.getImm() : 0;
int64_t RawImmValue = IsImm ? MCValOp.getImm() : 0;

// Allow either a signed or unsigned 32-bit immediate.
if (RawImmValue < -2147483648 || RawImmValue > 4294967295) {
Error(IDLoc, "set: argument must be between -2147483648 and 4294967295");
return;
}

// If the value was expressed as a large unsigned number, that's ok.
// We want to see if it "looks like" a small signed number.
int32_t ImmValue = RawImmValue;
// For 'set' you can't use 'or' with a negative operand on V9 because
// that would splat the sign bit across the upper half of the destination
// register, whereas 'set' is defined to zero the high 32 bits.
bool IsEffectivelyImm13 =
IsImm && ((is64Bit() ? 0 : -4096) <= ImmValue && ImmValue < 4096);
const MCExpr *ValExpr;
if (IsImm)
ValExpr = MCConstantExpr::create(ImmValue, getContext());
Expand All @@ -446,7 +461,10 @@ void SparcAsmParser::expandSET(MCInst &Inst, SMLoc IDLoc,

MCOperand PrevReg = MCOperand::createReg(Sparc::G0);

if (!IsImm || (ImmValue & ~0x1fff)) {
// If not just a signed imm13 value, then either we use a 'sethi' with a
// following 'or', or a 'sethi' by itself if there are no more 1 bits.
// In either case, start with the 'sethi'.
if (!IsEffectivelyImm13) {
MCInst TmpInst;
const MCExpr *Expr =
SparcMCExpr::create(SparcMCExpr::VK_Sparc_HI, ValExpr, getContext());
Expand All @@ -458,10 +476,24 @@ void SparcAsmParser::expandSET(MCInst &Inst, SMLoc IDLoc,
PrevReg = MCRegOp;
}

if (!IsImm || ((ImmValue & 0x1fff) != 0 || ImmValue == 0)) {
// The low bits require touching in 3 cases:
// * A non-immediate value will always require both instructions.
// * An effectively imm13 value needs only an 'or' instruction.
// * Otherwise, an immediate that is not effectively imm13 requires the
// 'or' only if bits remain after clearing the 22 bits that 'sethi' set.
// If the low bits are known zeros, there's nothing to do.
// In the second case, and only in that case, must we NOT clear
// bits of the immediate value via the %lo() assembler function.
// Note also, the 'or' instruction doesn't mind a large value in the case
// where the operand to 'set' was 0xFFFFFzzz - it does exactly what you mean.
if (!IsImm || IsEffectivelyImm13 || (ImmValue & 0x3ff)) {
MCInst TmpInst;
const MCExpr *Expr =
SparcMCExpr::create(SparcMCExpr::VK_Sparc_LO, ValExpr, getContext());
const MCExpr *Expr;
if (IsEffectivelyImm13)
Expr = ValExpr;
else
Expr =
SparcMCExpr::create(SparcMCExpr::VK_Sparc_LO, ValExpr, getContext());
TmpInst.setLoc(IDLoc);
TmpInst.setOpcode(SP::ORri);
TmpInst.addOperand(MCRegOp);
Expand Down
8 changes: 8 additions & 0 deletions test/MC/Sparc/sparc-asm-errors.s
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Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
! RUN: not llvm-mc %s -arch=sparc -show-encoding 2>&1 | FileCheck %s
! RUN: not llvm-mc %s -arch=sparcv9 -show-encoding 2>&1 | FileCheck %s

! Test the lower and upper bounds of 'set'
! CHECK: argument must be between
set -2147483649, %o1
! CHECK: argument must be between
set 4294967296, %o1
72 changes: 70 additions & 2 deletions test/MC/Sparc/sparc-synthetic-instructions.s
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Original file line number Diff line number Diff line change
Expand Up @@ -27,13 +27,33 @@
! CHECK: or %g1, %lo(40000), %g1 ! encoding: [0x82,0x10,0b011000AA,A]
! CHECK: ! fixup A - offset: 0, value: %lo(40000), kind: fixup_sparc_lo10
set 40000, %g1
! CHECK: mov %lo(1), %g1 ! encoding: [0x82,0x10,0b001000AA,A]
! CHECK: ! fixup A - offset: 0, value: %lo(1), kind: fixup_sparc_lo10
! CHECK: mov 1, %g1 ! encoding: [0x82,0x10,0x20,0x01]
set 1, %g1
! CHECK: sethi %hi(32768), %g1 ! encoding: [0x03,0b00AAAAAA,A,A]
! CHECK: ! fixup A - offset: 0, value: %hi(32768), kind: fixup_sparc_hi22
set 32768, %g1

! Expect a 'sethi' without an 'or'.
! CHECK: sethi %hi(268431360), %o1 ! encoding: [0x13,0b00AAAAAA,A,A]
! CHECK: ! fixup A - offset: 0, value: %hi(268431360), kind: fixup_sparc_hi22
set 0x0ffff000, %o1

! CHECK: sethi %hi(268433408), %o1 ! encoding: [0x13,0b00AAAAAA,A,A]
! CHECK: ! fixup A - offset: 0, value: %hi(268433408), kind: fixup_sparc_hi22
set 0x0ffff800, %o1

! This is the boundary case that uses the lowest of the 22 bits in sethi.
! CHECK: sethi %hi(268434432), %o1 ! encoding: [0x13,0b00AAAAAA,A,A]
! CHECK: ! fixup A - offset: 0, value: %hi(268434432), kind: fixup_sparc_hi22
set 0x0ffffc00, %o1

! Now the synthetic instruction becomes two instructions.
! CHECK: sethi %hi(2147483647), %o1 ! encoding: [0x13,0b00AAAAAA,A,A]
! CHECK: ! fixup A - offset: 0, value: %hi(2147483647), kind: fixup_sparc_hi22
! CHECK: or %o1, %lo(2147483647), %o1 ! encoding: [0x92,0x12,0b011000AA,A]
! CHECK: ! fixup A - offset: 0, value: %lo(2147483647), kind: fixup_sparc_lo10
set 2147483647, %o1

! CHECK: xnor %g1, %g0, %g2 ! encoding: [0x84,0x38,0x40,0x00]
not %g1, %g2
! CHECK: xnor %g1, %g0, %g1 ! encoding: [0x82,0x38,0x40,0x00]
Expand Down Expand Up @@ -143,3 +163,51 @@
wr %i0, %tbr
! CHECK: wr %g0, 5, %tbr ! encoding: [0x81,0x98,0x20,0x05]
wr 5, %tbr

! The following tests exercise 'set' in such a way that its output differs
! depending on whether targeting V8 or V9.
!
! RUN: llvm-mc %s -arch=sparc -show-encoding | FileCheck %s --check-prefix=V8
! RUN: llvm-mc %s -arch=sparcv9 -show-encoding | FileCheck %s --check-prefix=V9

! V8: mov -1, %o1 ! encoding: [0x92,0x10,0x3f,0xff]
! V9: sethi %hi(-1), %o1 ! encoding: [0x13,0b00AAAAAA,A,A]
! V9: ! fixup A - offset: 0, value: %hi(-1), kind: fixup_sparc_hi22
! V9: or %o1, %lo(-1), %o1 ! encoding: [0x92,0x12,0b011000AA,A]
! V9: ! fixup A - offset: 0, value: %lo(-1), kind: fixup_sparc_lo10
set 0xffffffff, %o1

! V8: mov -2, %o1 ! encoding: [0x92,0x10,0x3f,0xfe]
! V9: sethi %hi(-2), %o1 ! encoding: [0x13,0b00AAAAAA,A,A]
! V9: ! fixup A - offset: 0, value: %hi(-2), kind: fixup_sparc_hi22
! V9: or %o1, %lo(-2), %o1 ! encoding: [0x92,0x12,0b011000AA,A]
! V9: ! fixup A - offset: 0, value: %lo(-2), kind: fixup_sparc_lo10
set 0xfffffffe, %o1

! V8: mov -16, %o1 ! encoding: [0x92,0x10,0x3f,0xf0]
! V9: sethi %hi(-16), %o1 ! encoding: [0x13,0b00AAAAAA,A,A]
! V9: ! fixup A - offset: 0, value: %hi(-16), kind: fixup_sparc_hi22
! V9: or %o1, %lo(-16), %o1 ! encoding: [0x92,0x12,0b011000AA,A]
! V9: ! fixup A - offset: 0, value: %lo(-16), kind: fixup_sparc_lo10
set 0xfffffff0, %o1

! V8: mov -256, %o1 ! encoding: [0x92,0x10,0x3f,0x00]
! V9: sethi %hi(-256), %o1 ! encoding: [0x13,0b00AAAAAA,A,A]
! V9: ! fixup A - offset: 0, value: %hi(-256), kind: fixup_sparc_hi22
! V9: or %o1, %lo(-256), %o1 ! encoding: [0x92,0x12,0b011000AA,A]
! V9: ! fixup A - offset: 0, value: %lo(-256), kind: fixup_sparc_lo10
set 0xffffff00, %o1

! V8: mov -4096, %o1 ! encoding: [0x92,0x10,0x30,0x00]
! V9: sethi %hi(-4096), %o1 ! encoding: [0x13,0b00AAAAAA,A,A]
! V9: ! fixup A - offset: 0, value: %hi(-4096), kind: fixup_sparc_hi22
set 0xfffff000, %o1

! These results are the same for V8 and V9, so this test could have
! been with the others that weren't segregated by architecture,
! but logically it belongs here as a boundary case.
! V8: sethi %hi(-8192), %o1 ! encoding: [0x13,0b00AAAAAA,A,A]
! V8: ! fixup A - offset: 0, value: %hi(-8192), kind: fixup_sparc_hi22
! V9: sethi %hi(-8192), %o1 ! encoding: [0x13,0b00AAAAAA,A,A]
! V9: ! fixup A - offset: 0, value: %hi(-8192), kind: fixup_sparc_hi22
set 0xffffe000, %o1

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