diff options
| -rw-r--r-- | lib/Target/ARM/ARMAddressingModes.h | 37 | ||||
| -rw-r--r-- | lib/Target/ARM/AsmPrinter/ARMInstPrinter.cpp | 2 | ||||
| -rw-r--r-- | test/MC/Disassembler/arm-tests.txt | 3 |
3 files changed, 41 insertions, 1 deletions
diff --git a/lib/Target/ARM/ARMAddressingModes.h b/lib/Target/ARM/ARMAddressingModes.h index ea62c3330e..45b37b1cef 100644 --- a/lib/Target/ARM/ARMAddressingModes.h +++ b/lib/Target/ARM/ARMAddressingModes.h @@ -193,6 +193,43 @@ namespace ARM_AM { return rotl32(Arg, RotAmt) | ((RotAmt>>1) << 8); } + /// getSOImmValOneRotate - Try to handle Imm with an immediate shifter + /// operand, computing the rotate amount to use. If this immediate value + /// cannot be handled with a single shifter-op, return 0. + static unsigned getSOImmValOneRotate(unsigned Imm) { + // A5.2.4 Constants with multiple encodings + // The lowest unsigned value of rotation wins! + for (unsigned R = 1; R <= 15; ++R) + if ((Imm & rotr32(~255U, 2*R)) == 0) + return 2*R; + + // Failed to find a suitable rotate amount. + return 0; + } + + /// getSOImmValOneOrNoRotate - Given a 32-bit immediate, if it is something + /// that can fit into a shifter_operand immediate operand, return the 12-bit + /// encoding for it. If not, return -1. This is different from getSOImmVal() + /// in that getSOImmVal() is used during codegen, for example, + /// rewriteARMFrameIndex() where return value of -1 is not considered fatal. + /// + /// The current consumer of this API is printSOImm() within ARMInstPrinter.cpp + /// where return value of -1 indicates that the Arg is not a valid so_imm val! + static inline int getSOImmValOneOrNoRotate(unsigned Arg) { + // 8-bit (or less) immediates are trivially shifter_operands with a rotate + // of zero. + if ((Arg & ~255U) == 0) return Arg; + + unsigned RotAmt = getSOImmValOneRotate(Arg); + + // If this cannot be handled with a single shifter_op, bail out. + if (rotr32(~255U, RotAmt) & Arg) + return -1; + + // Encode this correctly. + return rotl32(Arg, RotAmt) | ((RotAmt>>1) << 8); + } + /// isSOImmTwoPartVal - Return true if the specified value can be obtained by /// or'ing together two SOImmVal's. static inline bool isSOImmTwoPartVal(unsigned V) { diff --git a/lib/Target/ARM/AsmPrinter/ARMInstPrinter.cpp b/lib/Target/ARM/AsmPrinter/ARMInstPrinter.cpp index ef5ead6e47..c73fa13091 100644 --- a/lib/Target/ARM/AsmPrinter/ARMInstPrinter.cpp +++ b/lib/Target/ARM/AsmPrinter/ARMInstPrinter.cpp @@ -225,7 +225,7 @@ void ARMInstPrinter::printOperand(const MCInst *MI, unsigned OpNo, static void printSOImm(raw_ostream &O, int64_t V, bool VerboseAsm, const MCAsmInfo *MAI) { // Break it up into two parts that make up a shifter immediate. - V = ARM_AM::getSOImmVal(V); + V = ARM_AM::getSOImmValOneOrNoRotate(V); assert(V != -1 && "Not a valid so_imm value!"); unsigned Imm = ARM_AM::getSOImmValImm(V); diff --git a/test/MC/Disassembler/arm-tests.txt b/test/MC/Disassembler/arm-tests.txt index 094a2d7372..7d10107bad 100644 --- a/test/MC/Disassembler/arm-tests.txt +++ b/test/MC/Disassembler/arm-tests.txt @@ -27,6 +27,9 @@ # CHECK: movt r8, #65535 0xff 0x8f 0x4f 0xe3 +# CHECK: mvnpls r7, #245, 2 +0xf5 0x71 0xf0 0x53 + # CHECK: pkhbt r8, r9, r10, lsl #4 0x1a 0x82 0x89 0xe6 |