[libcxx-commits] [PATCH] D156283: MIPS: unwind, don't save/restore hi/lo for R6

[YunQiang Su via Phabricator via libcxx-commits]

wzssyqa created this revision.
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HI/LO registers have been removed in MIPSr6.
Save and restore them only for pre-R6.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D156283

Files:
  libunwind/src/UnwindRegistersRestore.S
  libunwind/src/UnwindRegistersSave.S


Index: libunwind/src/UnwindRegistersSave.S
===================================================================
--- libunwind/src/UnwindRegistersSave.S
+++ libunwind/src/UnwindRegistersSave.S
@@ -174,11 +174,13 @@
   sw    $31, (4 * 31)($4)
   # Store return address to pc
   sw    $31, (4 * 32)($4)
+#if __mips_isa_rev < 6
   # hi and lo
   mfhi  $8
   sw    $8,  (4 * 33)($4)
   mflo  $8
   sw    $8,  (4 * 34)($4)
+#endif
 #ifdef __mips_hard_float
 #if __mips_fpr != 64
   sdc1  $f0, (4 * 36 + 8 * 0)($4)
@@ -255,11 +257,13 @@
   .endr
   # Store return address to pc
   sd    $31, (8 * 32)($4)
+#if __mips_isa_rev < 6
   # hi and lo
   mfhi  $8
   sd    $8,  (8 * 33)($4)
   mflo  $8
   sd    $8,  (8 * 34)($4)
+#endif
 #ifdef __mips_hard_float
   .irp i,FROM_0_TO_31
     sdc1 $f\i, (280+8*\i)($4)
Index: libunwind/src/UnwindRegistersRestore.S
===================================================================
--- libunwind/src/UnwindRegistersRestore.S
+++ libunwind/src/UnwindRegistersRestore.S
@@ -993,11 +993,13 @@
   ldc1  $f31, (4 * 36 + 8 * 31)($4)
 #endif
 #endif
+#if __mips_isa_rev < 6
   // restore hi and lo
   lw    $8, (4 * 33)($4)
   mthi  $8
   lw    $8, (4 * 34)($4)
   mtlo  $8
+#endif
   // r0 is zero
   lw    $1, (4 * 1)($4)
   lw    $2, (4 * 2)($4)
@@ -1054,11 +1056,13 @@
     ldc1 $f\i, (280+8*\i)($4)
   .endr
 #endif
+#if __mips_isa_rev < 6
   // restore hi and lo
   ld    $8, (8 * 33)($4)
   mthi  $8
   ld    $8, (8 * 34)($4)
   mtlo  $8
+#endif
   // r0 is zero
   ld    $1, (8 * 1)($4)
   ld    $2, (8 * 2)($4)


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