[SYCL][ESIMD] Remove optnone from ESIMD functions (#11986)

Previously we never had optnone in the SPIR-V due to the issue in
993fe5b,
but with that fixed we started seeing it and that broke some O0 tests.

Signed-off-by: Sarnie, Nick <nick.sarnie@intel.com>

llvm/lib/SYCLLowerIR/ESIMD/LowerESIMD.cpp

@@ -1835,6 +1835,17 @@ size_t SYCLLowerESIMDPass::runOnFunction(Function &F,
   SmallVector<CallInst *, 32> ESIMDIntrCalls;
   SmallVector<Instruction *, 8> ToErase;
 
+  // The VC backend doesn't support debugging, and trying to use
+  // non-optimized code often produces crashes or wrong answers.
+  // The recommendation from the VC team was always optimize code,
+  // even if the user requested no optimization. We already drop
+  // debugging flags in the SYCL runtime, so also drop optnone and
+  // noinline here.
+  if (isESIMD(F) && F.hasFnAttribute(Attribute::OptimizeNone)) {
+    F.removeFnAttr(Attribute::OptimizeNone);
+    F.removeFnAttr(Attribute::NoInline);
+  }
+
   for (Instruction &I : instructions(F)) {
     if (auto CastOp = dyn_cast<llvm::CastInst>(&I)) {
       llvm::Type *DstTy = CastOp->getDestTy();

llvm/test/SYCLLowerIR/ESIMD/optnone.ll

@@ -0,0 +1,20 @@
+; This ensures we remove optnone from ESIMD functions
+; RUN: opt < %s -passes=LowerESIMD -S | FileCheck %s
+
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-n8:16:32:64"
+target triple = "spir64-unknown-unknown"
+
+define dso_local spir_func void @esimd() #0 !sycl_explicit_simd !0 {
+; CHECK: void @esimd() #[[#ESIMDAttr:]]
+  ret void
+}
+
+define dso_local spir_func void @sycl() #0 {
+; CHECK: spir_func void @sycl() #[[#SYCLAttr:]]
+  ret void
+}
+; CHECK: attributes #[[#ESIMDAttr]] =
+; CHECK-NOT: optnone
+; CHECK: attributes #[[#SYCLAttr]] = {{{.*}}optnone{{.*}}}
+attributes #0 = { noinline optnone convergent }
+!0 = !{}