[OpenCL] Ignore parentheses for sampler initialization

The sampler handling logic in SemaInit.cpp would inadvertently treat
parentheses around sampler arguments as an implicit cast, leading to
an unreachable "can't implicitly cast lvalue to rvalue with
this cast kind".  Fix by ignoring parentheses once we are in the
sampler initializer case.

Differential Revision: https://reviews.llvm.org/D66080

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@368561 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaInit.cpp

@@ -8248,7 +8248,7 @@ ExprResult InitializationSequence::Perform(Sema &S,
       // argument passing.
       assert(Step->Type->isSamplerT() &&
              "Sampler initialization on non-sampler type.");
-      Expr *Init = CurInit.get();
+      Expr *Init = CurInit.get()->IgnoreParens();
       QualType SourceType = Init->getType();
       // Case 1
       if (Entity.isParameterKind()) {

test/SemaOpenCL/sampler_t.cl

@@ -10,6 +10,9 @@
 #define CLK_FILTER_NEAREST              0x10
 #define CLK_FILTER_LINEAR               0x20
 
+typedef float float4 __attribute__((ext_vector_type(4)));
+float4 read_imagef(read_only image1d_t, sampler_t, float);
+
 constant sampler_t glb_smp = CLK_ADDRESS_CLAMP_TO_EDGE | CLK_NORMALIZED_COORDS_TRUE | CLK_FILTER_LINEAR;
 constant sampler_t glb_smp2; // expected-error{{variable in constant address space must be initialized}}
 global sampler_t glb_smp3 = CLK_ADDRESS_CLAMP_TO_EDGE | CLK_NORMALIZED_COORDS_TRUE | CLK_FILTER_NEAREST; // expected-error{{sampler type cannot be used with the __local and __global address space qualifiers}} expected-error {{global sampler requires a const or constant address space qualifier}}
@@ -74,3 +77,7 @@ void bar() {
   foo(smp1+1); //expected-error{{invalid operands to binary expression ('sampler_t' and 'int')}}
 }
 
+void smp_args(read_only image1d_t image) {
+  // Test that parentheses around sampler arguments are ignored.
+  float4 res = read_imagef(image, (glb_smp10), 0.0f);
+}