[AMDGPU] Add verification for amdgcn.init.exec.from.input #128172

ro-i · 2025-02-21T13:21:25Z

Check that the input register is an inreg argument to the parent function. (See the comment in IntrinsicsAMDGPU.td.)

This LLVM defect was identified via the AMD Fuzzing project.

Check that the input register is an inreg argument to the parent function. (See the comment in `IntrinsicsAMDGPU.td`.) This LLVM defect was identified via the AMD Fuzzing project.

llvmbot · 2025-02-21T13:22:00Z

@llvm/pr-subscribers-backend-amdgpu

@llvm/pr-subscribers-llvm-ir

Author: Robert Imschweiler (ro-i)

Changes

Check that the input register is an inreg argument to the parent function. (See the comment in IntrinsicsAMDGPU.td.)

This LLVM defect was identified via the AMD Fuzzing project.

Full diff: https://github.com/llvm/llvm-project/pull/128172.diff

2 Files Affected:

(modified) llvm/lib/IR/Verifier.cpp (+15)
(added) llvm/test/Verifier/AMDGPU/intrinsic-amdgpu-init-exec-from-input.ll (+27)

diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 8432779c107de..55923fd56a109 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -6369,6 +6369,21 @@ void Verifier::visitIntrinsicCall(Intrinsic::ID ID, CallBase &Call) {
           "VGPR arguments must not have the `inreg` attribute", &Call);
     break;
   }
+  case Intrinsic::amdgcn_init_exec_from_input: {
+    const Value *InputVal = Call.getOperand(0);
+    bool InRegArgFound = false;
+    for (const Argument &Arg : Call.getCaller()->args()) {
+      if (Arg.hasInRegAttr() && &Arg == InputVal) {
+        InRegArgFound = true;
+        break;
+      }
+    }
+    Check(InRegArgFound,
+          "only inreg arguments to the parent function are valid as inputs to "
+          "this intrinsic",
+          &Call);
+    break;
+  }
   case Intrinsic::amdgcn_set_inactive_chain_arg: {
     auto CallerCC = Call.getCaller()->getCallingConv();
     switch (CallerCC) {
diff --git a/llvm/test/Verifier/AMDGPU/intrinsic-amdgpu-init-exec-from-input.ll b/llvm/test/Verifier/AMDGPU/intrinsic-amdgpu-init-exec-from-input.ll
new file mode 100644
index 0000000000000..5e4a6638dc170
--- /dev/null
+++ b/llvm/test/Verifier/AMDGPU/intrinsic-amdgpu-init-exec-from-input.ll
@@ -0,0 +1,27 @@
+; RUN: sed -e '/^; MARK$/,$d' %s | not llc -mtriple=amdgcn -mcpu=gfx942 2>&1 | FileCheck %s
+; RUN: sed -e '1,/^; MARK$/d' %s | llc -mtriple=amdgcn -mcpu=gfx942 -filetype=null
+
+; Function Attrs: convergent nocallback nofree nounwind willreturn
+declare void @llvm.amdgcn.init.exec.from.input(i32, i32 immarg) #0
+attributes #0 = { convergent nocallback nofree nounwind willreturn }
+
+; CHECK: only inreg arguments to the parent function are valid as inputs to this intrinsic
+; CHECK-NEXT: call void @llvm.amdgcn.init.exec.from.input(i32 0, i32 0)
+define amdgpu_ps void @init_exec_from_input_fail_immarg(i32 inreg %a, i32 %b) {
+  call void @llvm.amdgcn.init.exec.from.input(i32 0, i32 0)
+  ret void
+}
+
+; CHECK: only inreg arguments to the parent function are valid as inputs to this intrinsic
+; CHECK-NEXT: call void @llvm.amdgcn.init.exec.from.input(i32 %b, i32 0)
+define amdgpu_ps void @init_exec_from_input_fail_not_inreg(i32 inreg %a, i32 %b) {
+  call void @llvm.amdgcn.init.exec.from.input(i32 %b, i32 0)
+  ret void
+}
+
+; MARK
+
+define amdgpu_ps void @init_exec_from_input_success(i32 inreg %a, i32 %b) {
+  call void @llvm.amdgcn.init.exec.from.input(i32 %a, i32 0)
+  ret void
+}