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author | Jim Grosbach <grosbach@apple.com> | 2012-03-19 21:32:32 +0000 |
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committer | Jim Grosbach <grosbach@apple.com> | 2012-03-19 21:32:32 +0000 |
commit | fa1f74470a51a57b7b8feb4c4ba18501c3f2709a (patch) | |
tree | 3ddad1935c926a20119706035a2cbfc0259032be /lib/Target | |
parent | ceee984302a1cf1d659a186cf94149c779866da5 (diff) | |
download | external_llvm-fa1f74470a51a57b7b8feb4c4ba18501c3f2709a.zip external_llvm-fa1f74470a51a57b7b8feb4c4ba18501c3f2709a.tar.gz external_llvm-fa1f74470a51a57b7b8feb4c4ba18501c3f2709a.tar.bz2 |
ARM branch relaxation for unconditional t1 branches.
rdar://11059157
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153055 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target')
-rw-r--r-- | lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp b/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp index d3a3d3a..25849ee 100644 --- a/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp +++ b/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp @@ -167,6 +167,7 @@ static unsigned getRelaxedOpcode(unsigned Op) { case ARM::tBcc: return ARM::t2Bcc; case ARM::tLDRpciASM: return ARM::t2LDRpci; case ARM::tADR: return ARM::t2ADR; + case ARM::tB: return ARM::t2B; } } @@ -181,6 +182,16 @@ bool ARMAsmBackend::fixupNeedsRelaxation(const MCFixup &Fixup, const MCInstFragment *DF, const MCAsmLayout &Layout) const { switch ((unsigned)Fixup.getKind()) { + case ARM::fixup_arm_thumb_br: { + // Relaxing tB to t2B. tB has a signed 12-bit displacement with the + // low bit being an implied zero. There's an implied +4 offset for the + // branch, so we adjust the other way here to determine what's + // encodable. + // + // Relax if the value is too big for a (signed) i8. + int64_t Offset = int64_t(Value) - 4; + return Offset > 2046 || Offset < -2048; + } case ARM::fixup_arm_thumb_bcc: { // Relaxing tBcc to t2Bcc. tBcc has a signed 9-bit displacement with the // low bit being an implied zero. There's an implied +4 offset for the |