[Mlir-commits] [mlir] ec3cbe9 - [mlir][LLVM] add `llvm.ssa.copy` intrinsic

[Markus Böck]

Author: Markus Böck
Date: 2023-07-19T09:53:28+02:00
New Revision: ec3cbe92c009297e093552c360d57b023a422255

URL: https://github.com/llvm/llvm-project/commit/ec3cbe92c009297e093552c360d57b023a422255
DIFF: https://github.com/llvm/llvm-project/commit/ec3cbe92c009297e093552c360d57b023a422255.diff

LOG: [mlir][LLVM] add `llvm.ssa.copy` intrinsic

This is quite the niche intrinsic, whose whole purpose is to be able to essentially split an SSA value to be able to attach additional information to the new value.
It therefore really acts like a noop that just passes through its argument. It interestingly does not have any support in CodeGen and is therefore required to also be deleted by any pass creating it.

Differential Revision: https://reviews.llvm.org/D155678

Added: 
    

Modified: 
    mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td
    mlir/test/Target/LLVMIR/Import/intrinsic.ll
    mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir

Removed: 
    


################################################################################
diff  --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td
index d131a493d1e5ea..94c36874a49619 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td
@@ -419,6 +419,13 @@ def LLVM_USHLSat : LLVM_BinarySameArgsIntrOpI<"ushl.sat">;
 def LLVM_AssumeOp
   : LLVM_ZeroResultIntrOp<"assume", []>, Arguments<(ins I1:$cond)>;
 
+def LLVM_SSACopyOp : LLVM_OneResultIntrOp<"ssa.copy", [], [0],
+                                            [Pure, SameOperandsAndResultType]> {
+  let arguments = (ins AnyType:$operand);
+
+  let assemblyFormat = "$operand attr-dict `:` type($operand)";
+}
+
 def LLVM_IsConstantOp : LLVM_IntrOp<"is.constant", [], [0], [Pure], 1> {
   let arguments = (ins LLVM_Type:$val);
   let results = (outs I1:$res);

diff  --git a/mlir/test/Target/LLVMIR/Import/intrinsic.ll b/mlir/test/Target/LLVMIR/Import/intrinsic.ll
index 34f0b5a96ed658..a0aa4aee4b5128 100644
--- a/mlir/test/Target/LLVMIR/Import/intrinsic.ll
+++ b/mlir/test/Target/LLVMIR/Import/intrinsic.ll
@@ -850,6 +850,13 @@ define void @vector_predication_intrinsics(<8 x i32> %0, <8 x i32> %1, <8 x floa
   ret void
 }
 
+; CHECK-LABEL:  llvm.func @ssa_copy
+define float @ssa_copy(float %0) {
+  ; CHECK: %{{.*}} = llvm.intr.ssa.copy %{{.*}} : f32
+  %2 = call float @llvm.ssa.copy.f32(float %0)
+  ret float %2
+}
+
 declare float @llvm.fmuladd.f32(float, float, float)
 declare <8 x float> @llvm.fmuladd.v8f32(<8 x float>, <8 x float>, <8 x float>)
 declare float @llvm.fma.f32(float, float, float)
@@ -1065,3 +1072,4 @@ declare <8 x ptr> @llvm.vp.inttoptr.v8p0.v8i64(<8 x i64>, <8 x i1>, i32)
 declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture)
 declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture)
 declare void @llvm.assume(i1)
+declare float @llvm.ssa.copy.f32(float returned)

diff  --git a/mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir b/mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir
index 674e8637134832..d6c685541d2a26 100644
--- a/mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir
+++ b/mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir
@@ -932,6 +932,13 @@ llvm.func @lifetime(%p: !llvm.ptr) {
   llvm.return
 }
 
+// CHECK-LABEL: @ssa_copy
+llvm.func @ssa_copy(%arg: f32) -> f32 {
+  // CHECK: call float @llvm.ssa.copy
+  %0 = llvm.intr.ssa.copy %arg : f32
+  llvm.return %0 : f32
+}
+
 // Check that intrinsics are declared with appropriate types.
 // CHECK-DAG: declare float @llvm.fma.f32(float, float, float)
 // CHECK-DAG: declare <8 x float> @llvm.fma.v8f32(<8 x float>, <8 x float>, <8 x float>) #0
@@ -1085,3 +1092,4 @@ llvm.func @lifetime(%p: !llvm.ptr) {
 // CHECK-DAG: declare <2 x i32> @llvm.vector.extract.v2i32.v8i32(<8 x i32>, i64 immarg)
 // CHECK-DAG: declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture)
 // CHECK-DAG: declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture)
+// CHECK-DAG: declare float @llvm.ssa.copy.f32(float returned)