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, 16 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 98f7d877c05..ce3255c081b 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4768,22 +4768,8 @@ void SelectionDAGBuilder::visitTargetIntrinsic(const CallInst &I,
 
   // Add all operands of the call to the operand list.
   for (unsigned i = 0, e = I.getNumArgOperands(); i != e; ++i) {
-    const Value *Arg = I.getArgOperand(i);
-    if (!I.paramHasAttr(i, Attribute::ImmArg)) {
-      Ops.push_back(getValue(Arg));
-      continue;
-    }
-
-    // Use TargetConstant instead of a regular constant for immarg.
-    EVT VT = TLI.getValueType(*DL, Arg->getType(), true);
-    if (const ConstantInt *CI = dyn_cast<ConstantInt>(Arg)) {
-      assert(CI->getBitWidth() <= 64 &&
-             "large intrinsic immediates not handled");
-      Ops.push_back(DAG.getTargetConstant(*CI, SDLoc(), VT));
-    } else {
-      Ops.push_back(
-          DAG.getTargetConstantFP(*cast<ConstantFP>(Arg), SDLoc(), VT));
-    }
+    SDValue Op = getValue(I.getArgOperand(i));
+    Ops.push_back(Op);
   }
 
   SmallVector<EVT, 4> ValueVTs;