[mips] Fix 64-bit address loading in case of applying 32-bit mask to the result

If result of 64-bit address loading combines with 32-bit mask, LLVM
tries to optimize the code and remove "redundant" loading of upper
32-bits of the address. It leads to incorrect code on MIPS64 targets.

MIPS backend creates the following chain of commands to load 64-bit
address in the `MipsTargetLowering::getAddrNonPICSym64` method:
```
(add (shl (add (shl (add %highest(sym), %higher(sym)),
                    16),
               %hi(sym)),
          16),
     %lo(%sym))
```

If the mask presents, LLVM decides to optimize the chain of commands. It
really does not make sense to load upper 32-bits because the 0x0fffffff
mask anyway clears them. After removing redundant commands we get this
chain:
```
(add (shl (%hi(sym), 16), %lo(%sym))
```

There is no patterns matched `(MipsHi (i64 symbol))`. Due a bug in `SYM_32`
predicate definition, backend incorrectly selects a pattern for a 32-bit
symbols and uses the `lui` instruction for loading `%hi(sym)`.

As a result we get incorrect set of instructions with unnecessary 16-bit
left shifting:
```
lui     at,0x0
    R_MIPS_HI16     foo
dsll    at,at,0x10
daddiu  at,at,0
    R_MIPS_LO16     foo
```

This patch resolves two problems:
- Fix `SYM_32/SYM_64` predicates to prevent selection of patterns dedicated
  to 32-bit symbols in case of using N64 ABI.
- Add missed patterns for 64-bit symbols for `%hi/%lo`.

Fix PR42736.

Differential Revision: https://reviews.llvm.org/D66228

llvm-svn: 370268

3 files changed, 39 insertions, 2 deletions

diff --git a/llvm/lib/Target/Mips/Mips.td b/llvm/lib/Target/Mips/Mips.td
index 7b83ea8535a..52f400f91f8 100644
--- a/llvm/lib/Target/Mips/Mips.td
+++ b/llvm/lib/Target/Mips/Mips.td
@@ -25,6 +25,8 @@ class PredicateControl {
   list<Predicate> GPRPredicates = [];
   // Predicates for the PTR size such as IsPTR64bit
   list<Predicate> PTRPredicates = [];
+  // Predicates for a symbol's size such as hasSym32.
+  list<Predicate> SYMPredicates = [];
   // Predicates for the FGR size and layout such as IsFP64bit
   list<Predicate> FGRPredicates = [];
   // Predicates for the instruction group membership such as ISA's.
@@ -38,6 +40,7 @@ class PredicateControl {
   list<Predicate> Predicates = !listconcat(EncodingPredicates,
                                            GPRPredicates,
                                            PTRPredicates,
+                                           SYMPredicates,
                                            FGRPredicates,
                                            InsnPredicates,
                                            HardFloatPredicate,
diff --git a/llvm/lib/Target/Mips/Mips64InstrInfo.td b/llvm/lib/Target/Mips/Mips64InstrInfo.td
index 7f35280f793..b2ae5dea4d7 100644
--- a/llvm/lib/Target/Mips/Mips64InstrInfo.td
+++ b/llvm/lib/Target/Mips/Mips64InstrInfo.td
@@ -682,6 +682,20 @@ let AdditionalPredicates = [NotInMicroMips] in {
                 (DADDiu GPR64:$hi, tjumptable:$lo)>, ISA_MIPS3, GPR_64, SYM_64;
   def : MipsPat<(add GPR64:$hi, (MipsHigher (i64 tconstpool:$lo))),
                 (DADDiu GPR64:$hi, tconstpool:$lo)>, ISA_MIPS3, GPR_64, SYM_64;
+  def : MipsPat<(add GPR64:$hi, (MipsHigher (i64 texternalsym:$lo))),
+                (DADDiu GPR64:$hi, texternalsym:$lo)>,
+                ISA_MIPS3, GPR_64, SYM_64;
+
+  def : MipsPat<(MipsHi (i64 tglobaladdr:$in)),
+                (DADDiu ZERO_64, tglobaladdr:$in)>, ISA_MIPS3, GPR_64, SYM_64;
+  def : MipsPat<(MipsHi (i64 tblockaddress:$in)),
+                (DADDiu ZERO_64, tblockaddress:$in)>, ISA_MIPS3, GPR_64, SYM_64;
+  def : MipsPat<(MipsHi (i64 tjumptable:$in)),
+                (DADDiu ZERO_64, tjumptable:$in)>, ISA_MIPS3, GPR_64, SYM_64;
+  def : MipsPat<(MipsHi (i64 tconstpool:$in)),
+                (DADDiu ZERO_64, tconstpool:$in)>, ISA_MIPS3, GPR_64, SYM_64;
+  def : MipsPat<(MipsHi (i64 texternalsym:$in)),
+                (DADDiu ZERO_64, texternalsym:$in)>, ISA_MIPS3, GPR_64, SYM_64;
 
   def : MipsPat<(add GPR64:$hi, (MipsHi (i64 tglobaladdr:$lo))),
                 (DADDiu GPR64:$hi, tglobaladdr:$lo)>, ISA_MIPS3, GPR_64, SYM_64;
@@ -692,6 +706,23 @@ let AdditionalPredicates = [NotInMicroMips] in {
                 (DADDiu GPR64:$hi, tjumptable:$lo)>, ISA_MIPS3, GPR_64, SYM_64;
   def : MipsPat<(add GPR64:$hi, (MipsHi (i64 tconstpool:$lo))),
                 (DADDiu GPR64:$hi, tconstpool:$lo)>, ISA_MIPS3, GPR_64, SYM_64;
+  def : MipsPat<(add GPR64:$hi, (MipsHi (i64 texternalsym:$lo))),
+                (DADDiu GPR64:$hi, texternalsym:$lo)>,
+                ISA_MIPS3, GPR_64, SYM_64;
+
+  def : MipsPat<(MipsLo (i64 tglobaladdr:$in)),
+                (DADDiu ZERO_64, tglobaladdr:$in)>, ISA_MIPS3, GPR_64, SYM_64;
+  def : MipsPat<(MipsLo (i64 tblockaddress:$in)),
+                (DADDiu ZERO_64, tblockaddress:$in)>, ISA_MIPS3, GPR_64, SYM_64;
+  def : MipsPat<(MipsLo (i64 tjumptable:$in)),
+                (DADDiu ZERO_64, tjumptable:$in)>, ISA_MIPS3, GPR_64, SYM_64;
+  def : MipsPat<(MipsLo (i64 tconstpool:$in)),
+                (DADDiu ZERO_64, tconstpool:$in)>, ISA_MIPS3, GPR_64, SYM_64;
+  def : MipsPat<(MipsLo (i64 tglobaltlsaddr:$in)),
+                (DADDiu ZERO_64, tglobaltlsaddr:$in)>,
+                ISA_MIPS3, GPR_64, SYM_64;
+  def : MipsPat<(MipsLo (i64 texternalsym:$in)),
+                (DADDiu ZERO_64, texternalsym:$in)>, ISA_MIPS3, GPR_64, SYM_64;
 
   def : MipsPat<(add GPR64:$hi, (MipsLo (i64 tglobaladdr:$lo))),
                 (DADDiu GPR64:$hi, tglobaladdr:$lo)>, ISA_MIPS3, GPR_64, SYM_64;
@@ -705,6 +736,9 @@ let AdditionalPredicates = [NotInMicroMips] in {
   def : MipsPat<(add GPR64:$hi, (MipsLo (i64 tglobaltlsaddr:$lo))),
                 (DADDiu GPR64:$hi, tglobaltlsaddr:$lo)>, ISA_MIPS3, GPR_64,
                 SYM_64;
+  def : MipsPat<(add GPR64:$hi, (MipsLo (i64 texternalsym:$lo))),
+                (DADDiu GPR64:$hi, texternalsym:$lo)>,
+                ISA_MIPS3, GPR_64, SYM_64;
 }
 
 // gp_rel relocs
diff --git a/llvm/lib/Target/Mips/MipsInstrInfo.td b/llvm/lib/Target/Mips/MipsInstrInfo.td
index 49413c90d01..b42d718b7e8 100644
--- a/llvm/lib/Target/Mips/MipsInstrInfo.td
+++ b/llvm/lib/Target/Mips/MipsInstrInfo.td
@@ -211,9 +211,9 @@ def HasCnMips    :    Predicate<"Subtarget->hasCnMips()">,
                       AssemblerPredicate<"FeatureCnMips">;
 def NotCnMips    :    Predicate<"!Subtarget->hasCnMips()">,
                       AssemblerPredicate<"!FeatureCnMips">;
-def IsSym32     :     Predicate<"Subtarget->HasSym32()">,
+def IsSym32     :     Predicate<"Subtarget->hasSym32()">,
                       AssemblerPredicate<"FeatureSym32">;
-def IsSym64     :     Predicate<"!Subtarget->HasSym32()">,
+def IsSym64     :     Predicate<"!Subtarget->hasSym32()">,
                       AssemblerPredicate<"!FeatureSym32">;
 def IsN64       :     Predicate<"Subtarget->isABI_N64()">;
 def IsNotN64    :     Predicate<"!Subtarget->isABI_N64()">;