[llvm] [GISel] Add LookThroughInstrs for getIConstantVRegVal and getIConstan… (PR #68327)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-globalisel

<details>
<summary>Changes</summary>

…tVRegSExtVal

The implementation of these methods uses getIConstantVRegValWithLookThrough with LookThroughInstrs argument set to false. By adding the optional argument to getIConstantVRegVal and getIConstantVRegSExtVal we can take advantage of the already built look through functionality.

---
Full diff: https://github.com/llvm/llvm-project/pull/68327.diff


1 Files Affected:

- (modified) llvm/lib/CodeGen/GlobalISel/Utils.cpp (+5-3) 


``````````diff
diff --git a/llvm/lib/CodeGen/GlobalISel/Utils.cpp b/llvm/lib/CodeGen/GlobalISel/Utils.cpp
index 473c3f452f8b1d9..bc97acd9d76f07c 100644
--- a/llvm/lib/CodeGen/GlobalISel/Utils.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/Utils.cpp
@@ -290,9 +290,10 @@ void llvm::reportGISelFailure(MachineFunction &MF, const TargetPassConfig &TPC,
 }
 
 std::optional<APInt> llvm::getIConstantVRegVal(Register VReg,
-                                               const MachineRegisterInfo &MRI) {
+                                               const MachineRegisterInfo &MRI,
+                                               bool LookThroughInstrs = false) {
   std::optional<ValueAndVReg> ValAndVReg = getIConstantVRegValWithLookThrough(
-      VReg, MRI, /*LookThroughInstrs*/ false);
+      VReg, MRI, LookThroughInstrs);
   assert((!ValAndVReg || ValAndVReg->VReg == VReg) &&
          "Value found while looking through instrs");
   if (!ValAndVReg)
@@ -301,7 +302,8 @@ std::optional<APInt> llvm::getIConstantVRegVal(Register VReg,
 }
 
 std::optional<int64_t>
-llvm::getIConstantVRegSExtVal(Register VReg, const MachineRegisterInfo &MRI) {
+llvm::getIConstantVRegSExtVal(Register VReg, const MachineRegisterInfo &MRI,
+                              bool LookThroughInstrs = false) {
   std::optional<APInt> Val = getIConstantVRegVal(VReg, MRI);
   if (Val && Val->getBitWidth() <= 64)
     return Val->getSExtValue();

``````````

</details>


https://github.com/llvm/llvm-project/pull/68327