[AMDGPU] Enhance verification of amdgcn.cs.chain intrinsic (#128162)
Make sure that this intrinsic is being followed by unreachable.
This LLVM defect was identified via the AMD Fuzzing project.
Thanks to @rovka for helping me solve this issue!
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 8432779..58fd575 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -6367,6 +6367,8 @@
"SGPR arguments must have the `inreg` attribute", &Call);
Check(!Call.paramHasAttr(3, Attribute::InReg),
"VGPR arguments must not have the `inreg` attribute", &Call);
+ Check(isa_and_present<UnreachableInst>(Call.getNextNode()),
+ "llvm.amdgcn.cs.chain must be followed by unreachable", &Call);
break;
}
case Intrinsic::amdgcn_set_inactive_chain_arg: {
diff --git a/llvm/test/Verifier/AMDGPU/intrinsic-amdgpu-cs-chain.ll b/llvm/test/Verifier/AMDGPU/intrinsic-amdgpu-cs-chain.ll
index b9e6e1e..e6fba2c 100644
--- a/llvm/test/Verifier/AMDGPU/intrinsic-amdgpu-cs-chain.ll
+++ b/llvm/test/Verifier/AMDGPU/intrinsic-amdgpu-cs-chain.ll
@@ -32,6 +32,13 @@
unreachable
}
+define amdgpu_cs_chain void @not_unreachable(ptr %fn, i32 %exec, <4 x i32> inreg %sgpr, { ptr, <3 x i32> } %vgpr) {
+ ; CHECK: llvm.amdgcn.cs.chain must be followed by unreachable
+ ; CHECK-NEXT: @llvm.amdgcn.cs.chain
+ call void(ptr, i32, <4 x i32>, { ptr, <3 x i32> }, i32, ...) @llvm.amdgcn.cs.chain(ptr %fn, i32 %exec, <4 x i32> inreg %sgpr, { ptr, <3 x i32> } %vgpr, i32 0)
+ ret void
+}
+
define void @bad_caller_default_cc(ptr %fn, i32 %exec, <4 x i32> inreg %sgpr, { ptr, <3 x i32> } %vgpr) {
; CHECK: Intrinsic can only be used from functions with the amdgpu_cs_chain or amdgpu_cs_chain_preserve calling conventions
; CHECK-NEXT: @llvm.amdgcn.set.inactive.chain.arg
