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6824f127f9
System z branches have a mask to select which of the 4 CC values should cause the branch to be taken. We can invert a branch by inverting the mask. However, not all instructions can produce all 4 CC values, so inverting the branch like this can lead to some oddities. For example, integer comparisons only produce a CC of 0 (equal), 1 (less) or 2 (greater). If an integer EQ is reversed to NE before instruction selection, the branch will test for 1 or 2. If instead the branch is reversed after instruction selection (by inverting the mask), it will test for 1, 2 or 3. Both are correct, but the second isn't really canonical. This patch therefore keeps track of which CC values are possible and uses this when inverting a mask. Although this is mostly cosmestic, it fixes undefined behavior for the CIJNLH in branch-08.ll. Another fix would have been to mask out bit 0 when generating the fused compare and branch, but the point of this patch is that we shouldn't need to do that in the first place. The patch also makes it easier to reuse CC results from other instructions. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187495 91177308-0d34-0410-b5e6-96231b3b80d8
91 lines
3.1 KiB
C++
91 lines
3.1 KiB
C++
//==- SystemZ.h - Top-Level Interface for SystemZ representation -*- C++ -*-==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the entry points for global functions defined in
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// the LLVM SystemZ backend.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SYSTEMZ_H
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#define SYSTEMZ_H
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#include "MCTargetDesc/SystemZMCTargetDesc.h"
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#include "llvm/Support/CodeGen.h"
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namespace llvm {
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class SystemZTargetMachine;
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class FunctionPass;
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namespace SystemZ {
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// Condition-code mask values.
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const unsigned CCMASK_0 = 1 << 3;
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const unsigned CCMASK_1 = 1 << 2;
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const unsigned CCMASK_2 = 1 << 1;
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const unsigned CCMASK_3 = 1 << 0;
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const unsigned CCMASK_ANY = CCMASK_0 | CCMASK_1 | CCMASK_2 | CCMASK_3;
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// Condition-code mask assignments for integer and floating-point
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// comparisons.
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const unsigned CCMASK_CMP_EQ = CCMASK_0;
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const unsigned CCMASK_CMP_LT = CCMASK_1;
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const unsigned CCMASK_CMP_GT = CCMASK_2;
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const unsigned CCMASK_CMP_NE = CCMASK_CMP_LT | CCMASK_CMP_GT;
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const unsigned CCMASK_CMP_LE = CCMASK_CMP_EQ | CCMASK_CMP_LT;
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const unsigned CCMASK_CMP_GE = CCMASK_CMP_EQ | CCMASK_CMP_GT;
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// Condition-code mask assignments for floating-point comparisons only.
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const unsigned CCMASK_CMP_UO = CCMASK_3;
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const unsigned CCMASK_CMP_O = CCMASK_ANY ^ CCMASK_CMP_UO;
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// All condition-code values produced by comparisons.
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const unsigned CCMASK_ICMP = CCMASK_0 | CCMASK_1 | CCMASK_2;
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const unsigned CCMASK_FCMP = CCMASK_0 | CCMASK_1 | CCMASK_2 | CCMASK_3;
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// Condition-code mask assignments for CS.
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const unsigned CCMASK_CS_EQ = CCMASK_0;
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const unsigned CCMASK_CS_NE = CCMASK_1;
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const unsigned CCMASK_CS = CCMASK_0 | CCMASK_1;
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// Return true if Val fits an LLILL operand.
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static inline bool isImmLL(uint64_t Val) {
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return (Val & ~0x000000000000ffffULL) == 0;
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}
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// Return true if Val fits an LLILH operand.
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static inline bool isImmLH(uint64_t Val) {
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return (Val & ~0x00000000ffff0000ULL) == 0;
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}
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// Return true if Val fits an LLIHL operand.
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static inline bool isImmHL(uint64_t Val) {
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return (Val & ~0x00000ffff00000000ULL) == 0;
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}
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// Return true if Val fits an LLIHH operand.
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static inline bool isImmHH(uint64_t Val) {
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return (Val & ~0xffff000000000000ULL) == 0;
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}
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// Return true if Val fits an LLILF operand.
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static inline bool isImmLF(uint64_t Val) {
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return (Val & ~0x00000000ffffffffULL) == 0;
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}
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// Return true if Val fits an LLIHF operand.
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static inline bool isImmHF(uint64_t Val) {
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return (Val & ~0xffffffff00000000ULL) == 0;
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}
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}
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FunctionPass *createSystemZISelDag(SystemZTargetMachine &TM,
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CodeGenOpt::Level OptLevel);
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FunctionPass *createSystemZLongBranchPass(SystemZTargetMachine &TM);
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} // end namespace llvm;
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#endif
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