Rename ppr_to_ppm pass to merge_ppr_ppm (#1688)

**Context:**
The `ppr_to_ppm` pass has been renamed to `merge_ppr_ppm` (same
functionality). A new `ppr_to_ppm` will handle decomposition of
non-Clifford PPRs into PPMs.

---------

Co-authored-by: David Ittah <[email protected]>

Author: sengthai

doc/releases/changelog-dev.md

@@ -16,7 +16,7 @@
 <h3>Breaking changes 💔</h3>
 
 * Catalyst has removed the `experimental_capture` keyword from the `qjit` decorator in favour of
-  unified behaviour with PennyLane. 
+  unified behaviour with PennyLane.
   [(#1657)](https://github.com/PennyLaneAI/catalyst/pull/1657)
 
   Instead of enabling program capture with Catalyst via `qjit(experimental_capture=True)`, program capture
@@ -42,6 +42,9 @@
 
   Disabling program capture can be done with `qml.capture.disable()`.
 
+* The `ppr_to_ppm` pass has been renamed to `merge_ppr_ppm` (same functionality). A new `ppr_to_ppm` will handle direct decomposition of PPRs into PPMs.
+  [(#1688)](https://github.com/PennyLaneAI/catalyst/pull/1688)
+
 <h3>Deprecations 👋</h3>
 
 <h3>Bug fixes 🐛</h3>
@@ -75,6 +78,7 @@
 This release contains contributions from (in alphabetical order):
 
 Joey Carter,
+Sengthai Heng,
 David Ittah,
 Christina Lee,
 Erick Ochoa Lopez,

frontend/catalyst/passes/__init__.py

@@ -37,8 +37,8 @@
     cancel_inverses,
     commute_ppr,
     ions_decomposition,
+    merge_ppr_ppm,
     merge_rotations,
-    ppr_to_ppm,
     to_ppr,
 )
 from catalyst.passes.pass_api import Pass, PassPlugin, apply_pass, apply_pass_plugin
@@ -53,5 +53,5 @@
     "PassPlugin",
     "apply_pass",
     "apply_pass_plugin",
-    "ppr_to_ppm",
+    "merge_ppr_ppm",
 )

frontend/catalyst/passes/builtin_passes.py

@@ -451,7 +451,7 @@ def circuit():
     return PassPipelineWrapper(qnode, "commute_ppr")
 
 
-def ppr_to_ppm(qnode):
+def merge_ppr_ppm(qnode):
     R"""
     Specify that the MLIR compiler pass for absorbing Clifford Pauli
     Product Rotation (PPR) operations, :math:`\exp{iP\tfrac{\pi}{4}}`,
@@ -477,7 +477,7 @@ def ppr_to_ppm(qnode):
         import pennylane as qml
         from catalyst import qjit, measure
 
-        ppm_passes = [("PPM",["to_ppr", "commute_ppr","ppr_to_ppm",])]
+        ppm_passes = [("PPM",["to_ppr", "commute_ppr","merge_ppr_ppm",])]
 
         @qjit(pipelines=ppm_passes, keep_intermediate=True, target="mlir")
         @qml.qnode(qml.device("lightning.qubit", wires=1))
@@ -498,4 +498,4 @@ def circuit():
         . . .
 
     """
-    return PassPipelineWrapper(qnode, "ppr_to_ppm")
+    return PassPipelineWrapper(qnode, "merge_ppr_ppm")

frontend/catalyst/passes/pass_api.py

@@ -376,5 +376,5 @@ def _API_name_to_pass_name():
         "ions_decomposition": "ions-decomposition",
         "to_ppr": "to_ppr",
         "commute_ppr": "commute_ppr",
-        "ppr_to_ppm": "ppr_to_ppm",
+        "merge_ppr_ppm": "merge_ppr_ppm",
     }

mlir/include/QEC/Transforms/Passes.td

@@ -37,7 +37,7 @@ def CommuteCliffordTPPRPass : Pass<"commute_ppr"> {
     let constructor = "catalyst::createCommuteCliffordTPPRPass()";
 }
 
-def CommuteCliffordPastPPMPass : Pass<"ppr_to_ppm"> {
+def CommuteCliffordPastPPMPass : Pass<"merge_ppr_ppm"> {
     let summary = "Absorb Clifford operations into Pauli Product Measurement operations.";
 
     let dependentDialects = [

mlir/lib/QEC/Transforms/CommuteCliffordPastPPM.cpp

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#define DEBUG_TYPE "ppr_to_ppm"
+#define DEBUG_TYPE "merge_ppr_ppm"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Debug.h"
 

mlir/lib/QEC/Transforms/commute_clifford_past_ppm.cpp

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#define DEBUG_TYPE "ppr_to_ppm"
+#define DEBUG_TYPE "merge_ppr_ppm"
 
 #include "llvm/Support/Debug.h"
 

mlir/test/QEC/CommuteCliffordPastPPMTest.mlir

@@ -12,9 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// RUN: quantum-opt --ppr_to_ppm --split-input-file -verify-diagnostics %s | FileCheck %s
+// RUN: quantum-opt --merge_ppr_ppm --split-input-file -verify-diagnostics %s | FileCheck %s
 
-func.func public @ppr_to_ppm_test_1(%q1: !quantum.bit) -> tensor<i1> {
+func.func public @merge_ppr_ppm_test_1(%q1: !quantum.bit) -> tensor<i1> {
 
     // CHECK-NOT:   qec.ppr["X"](4)
     // CHECK:       qec.ppm ["X"] %
@@ -25,7 +25,7 @@ func.func public @ppr_to_ppm_test_1(%q1: !quantum.bit) -> tensor<i1> {
     return %from_elements : tensor<i1>
 }
 
-func.func public @ppr_to_ppm_test_2(%q1: !quantum.bit) -> (tensor<i1>, !quantum.bit) {
+func.func public @merge_ppr_ppm_test_2(%q1: !quantum.bit) -> (tensor<i1>, !quantum.bit) {
 
     // CHECK-NOT:   qec.ppr["X"](4)
     // CHECK:       qec.ppm ["Z"](-1) %
@@ -36,7 +36,7 @@ func.func public @ppr_to_ppm_test_2(%q1: !quantum.bit) -> (tensor<i1>, !quantum.
     return %from_elements, %out_qubits : tensor<i1>, !quantum.bit
 }
 
-func.func public @ppr_to_ppm_test_3(%q1: !quantum.bit) -> (tensor<i1>, !quantum.bit) {
+func.func public @merge_ppr_ppm_test_3(%q1: !quantum.bit) -> (tensor<i1>, !quantum.bit) {
 
     // CHECK-NOT:   qec.ppr["X"](4)
     // CHECK:       qec.ppm ["Y"] %
@@ -47,7 +47,7 @@ func.func public @ppr_to_ppm_test_3(%q1: !quantum.bit) -> (tensor<i1>, !quantum.
     return %from_elements, %out_qubits : tensor<i1>, !quantum.bit
 }
 
-func.func public @ppr_to_ppm_test_4(%q1: !quantum.bit, %q2: !quantum.bit) -> (tensor<i1>, !quantum.bit) {
+func.func public @merge_ppr_ppm_test_4(%q1: !quantum.bit, %q2: !quantum.bit) -> (tensor<i1>, !quantum.bit) {
 
     // CHECK: [[q0:%.+]] = qec.ppr ["X"](8) %arg0 : !quantum.bit
     // CHECK-NOT: ["X"](4)
@@ -62,7 +62,7 @@ func.func public @ppr_to_ppm_test_4(%q1: !quantum.bit, %q2: !quantum.bit) -> (te
     return %from_elements, %out_qubits#0 : tensor<i1>, !quantum.bit
 }
 
-func.func public @ppr_to_ppm_test_5(%q1: !quantum.bit, %q2: !quantum.bit) -> (tensor<i1>, !quantum.bit) {
+func.func public @merge_ppr_ppm_test_5(%q1: !quantum.bit, %q2: !quantum.bit) -> (tensor<i1>, !quantum.bit) {
 
     // CHECK:       [[q0:%.+]] = qec.ppr ["X"](8) %arg0 : !quantum.bit
     // CHECK-NOT:   qec.ppr ["Y"](4)
@@ -77,7 +77,7 @@ func.func public @ppr_to_ppm_test_5(%q1: !quantum.bit, %q2: !quantum.bit) -> (te
     return %from_elements, %out_qubits#0 : tensor<i1>, !quantum.bit
 }
 
-func.func public @ppr_to_ppm_test_6(%q1: !quantum.bit, %q2: !quantum.bit) -> (tensor<i1>, !quantum.bit) {
+func.func public @merge_ppr_ppm_test_6(%q1: !quantum.bit, %q2: !quantum.bit) -> (tensor<i1>, !quantum.bit) {
 
     // CHECK: [[q1:%.+]]:2 = qec.ppr ["X", "X"](8) %arg0, %arg1
     // CHECK: [[m1:%.+]], [[o1:%.+]]:2 = qec.ppm ["X", "Z"] [[q1]]#0, [[q1]]#1