[llvm] [NVPTX] Fix segfault with i128 types in arrays (PR #120562)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-nvptx

Author: Valery Chernov (vvchernov)

<details>
<summary>Changes</summary>

- Process i128 array with custom ComputePTXValueVTs. The i128 elements should be handled and split into i64 types in the recursion.
- Add corresponding test

---
Full diff: https://github.com/llvm/llvm-project/pull/120562.diff


2 Files Affected:

- (modified) llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp (+11) 
- (added) llvm/test/CodeGen/NVPTX/i128-array.ll (+25) 


``````````diff
diff --git a/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp b/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
index ce94dded815b8f..4282965c3cddea 100644
--- a/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
@@ -198,6 +198,17 @@ static void ComputePTXValueVTs(const TargetLowering &TLI, const DataLayout &DL,
     return;
   }
 
+  // Given an array type, recursively traverse the elements with custom ComputePTXValueVTs.
+  if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
+    Type *EltTy = ATy->getElementType();
+    uint64_t EltSize = DL.getTypeAllocSize(EltTy);
+    for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i) {
+      ComputePTXValueVTs(TLI, DL, EltTy, ValueVTs, Offsets,
+                         StartingOffset + i * EltSize);
+    }
+    return;
+  }
+
   ComputeValueVTs(TLI, DL, Ty, TempVTs, &TempOffsets, StartingOffset);
   for (unsigned i = 0, e = TempVTs.size(); i != e; ++i) {
     EVT VT = TempVTs[i];
diff --git a/llvm/test/CodeGen/NVPTX/i128-array.ll b/llvm/test/CodeGen/NVPTX/i128-array.ll
new file mode 100644
index 00000000000000..4054d721d04863
--- /dev/null
+++ b/llvm/test/CodeGen/NVPTX/i128-array.ll
@@ -0,0 +1,25 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s -O0 -march=nvptx64 -mcpu=sm_20 | FileCheck %s
+
+define [2 x i128] @foo(i64 %a, i32 %b) {
+; CHECK-LABEL: foo(
+; CHECK:       {
+; CHECK-NEXT:    .reg .b32 %r<2>;
+; CHECK-NEXT:    .reg .b64 %rd<5>;
+; CHECK-EMPTY:
+; CHECK-NEXT:  // %bb.0:
+; CHECK-NEXT:    ld.param.u32 %r1, [foo_param_1];
+; CHECK-NEXT:    ld.param.u64 %rd1, [foo_param_0];
+; CHECK-NEXT:    shr.s64 %rd2, %rd1, 63;
+; CHECK-NEXT:    cvt.s64.s32 %rd3, %r1;
+; CHECK-NEXT:    shr.s64 %rd4, %rd3, 63;
+; CHECK-NEXT:    st.param.v2.b64 [func_retval0], {%rd1, %rd2};
+; CHECK-NEXT:    st.param.v2.b64 [func_retval0+16], {%rd3, %rd4};
+; CHECK-NEXT:    ret;
+  %1 = sext i64 %a to i128
+  %2 = sext i32 %b to i128
+  %3 = insertvalue [ 2 x i128 ] undef, i128 %1, 0
+  %4 = insertvalue [ 2 x i128 ] %3, i128 %2, 1
+
+  ret [ 2 x i128 ] %4
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/120562