Revert r372285 "GlobalISel: Don't materialize immarg arguments to intrinsics"

This broke the Chromium build, causing it to fail with e.g.

  fatal error: error in backend: Cannot select: t362: v4i32 = X86ISD::VSHLI t392, Constant:i8<15>

See llvm-commits thread of r372285 for details.

This also reverts r372286, r372287, r372288, r372289, r372290, r372291,
r372292, r372293, r372296, and r372297, which seemed to depend on the
main commit.

> Encode them directly as an imm argument to G_INTRINSIC*.
>
> Since now intrinsics can now define what parameters are required to be
> immediates, avoid using registers for them. Intrinsics could
> potentially want a constant that isn't a legal register type. Also,
> since G_CONSTANT is subject to CSE and legalization, transforms could
> potentially obscure the value (and create extra work for the
> selector). The register bank of a G_CONSTANT is also meaningful, so
> this could throw off future folding and legalization logic for AMDGPU.
>
> This will be much more convenient to work with than needing to call
> getConstantVRegVal and checking if it may have failed for every
> constant intrinsic parameter. AMDGPU has quite a lot of intrinsics wth
> immarg operands, many of which need inspection during lowering. Having
> to find the value in a register is going to add a lot of boilerplate
> and waste compile time.
>
> SelectionDAG has always provided TargetConstant for constants which
> should not be legalized or materialized in a register. The distinction
> between Constant and TargetConstant was somewhat fuzzy, and there was
> no automatic way to force usage of TargetConstant for certain
> intrinsic parameters. They were both ultimately ConstantSDNode, and it
> was inconsistently used. It was quite easy to mis-select an
> instruction requiring an immediate. For SelectionDAG, start emitting
> TargetConstant for these arguments, and using timm to match them.
>
> Most of the work here is to cleanup target handling of constants. Some
> targets process intrinsics through intermediate custom nodes, which
> need to preserve TargetConstant usage to match the intrinsic
> expectation. Pattern inputs now need to distinguish whether a constant
> is merely compatible with an operand or whether it is mandatory.
>
> The GlobalISelEmitter needs to treat timm as a special case of a leaf
> node, simlar to MachineBasicBlock operands. This should also enable
> handling of patterns for some G_* instructions with immediates, like
> G_FENCE or G_EXTRACT.
>
> This does include a workaround for a crash in GlobalISelEmitter when
> ARM tries to uses "imm" in an output with a "timm" pattern source.

llvm-svn: 372314

1 files changed, 2 insertions, 8 deletions

diff --git a/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp b/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
index 92420e697ce..af07f8f948f 100644
--- a/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
+++ b/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -373,13 +373,6 @@ LaneBitmask ScheduleDAGInstrs::getLaneMaskForMO(const MachineOperand &MO) const
   return TRI->getSubRegIndexLaneMask(SubReg);
 }
 
-bool ScheduleDAGInstrs::deadDefHasNoUse(const MachineOperand &MO) {
-  auto RegUse = CurrentVRegUses.find(MO.getReg());
-  if (RegUse == CurrentVRegUses.end())
-    return true;
-  return (RegUse->LaneMask & getLaneMaskForMO(MO)).none();
-}
-
 /// Adds register output and data dependencies from this SUnit to instructions
 /// that occur later in the same scheduling region if they read from or write to
 /// the virtual register defined at OperIdx.
@@ -409,7 +402,8 @@ void ScheduleDAGInstrs::addVRegDefDeps(SUnit *SU, unsigned OperIdx) {
   }
 
   if (MO.isDead()) {
-    assert(deadDefHasNoUse(MO) && "Dead defs should have no uses");
+    assert(CurrentVRegUses.find(Reg) == CurrentVRegUses.end() &&
+           "Dead defs should have no uses");
   } else {
     // Add data dependence to all uses we found so far.
     const TargetSubtargetInfo &ST = MF.getSubtarget();