[PATCH] D15721: [Sema] Fix ICE on casting a vector of bools to a vector of T

[George Burgess IV via cfe-commits]

george.burgess.iv added a reviewer: hfinkel.
george.burgess.iv updated this revision to Diff 46088.
george.burgess.iv added a comment.

+hfinkel as a reviewer, because `git` said he originally added the tests I'm removing.

I played around a bit, and it turns out that we don't generate correct machine code for bitvectors, and we get even more ICEs if we try to pass 3-bit bitvectors around. Awkward. This prompted me to talk with Chandler, who noted that we have no ABI for bitvectors, and that they might be useful for vector selects. Clang apparently does not support vector selects at the moment.

So, until we either support vector selects or get an ABI for this, disabling extended vectors of bools is probably our best bet. :)


http://reviews.llvm.org/D15721

Files:
  lib/Sema/SemaType.cpp
  test/CodeGen/convertvector.c
  test/Sema/ext_vector_casts.c
  test/SemaOpenCL/bool-vectors.cl

Index: test/SemaOpenCL/bool-vectors.cl
===================================================================
--- /dev/null
+++ test/SemaOpenCL/bool-vectors.cl
@@ -0,0 +1,3 @@
+// RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only
+
+typedef __attribute__((ext_vector_type(16))) _Bool bool8; // expected-error{{invalid vector element type 'bool'}}
Index: test/Sema/ext_vector_casts.c
===================================================================
--- test/Sema/ext_vector_casts.c
+++ test/Sema/ext_vector_casts.c
@@ -1,5 +1,7 @@
 // RUN: %clang_cc1 -triple x86_64-apple-macos10.7.0 -fsyntax-only -verify -fno-lax-vector-conversions -Wconversion %s
 
+typedef __attribute__((ext_vector_type(8))) _Bool BoolVector; // expected-error {{invalid vector element type '_Bool'}}
+
 typedef __attribute__(( ext_vector_type(2) )) float float2;
 typedef __attribute__(( ext_vector_type(3) )) float float3;
 typedef __attribute__(( ext_vector_type(4) )) int int4;
Index: test/CodeGen/convertvector.c
===================================================================
--- test/CodeGen/convertvector.c
+++ test/CodeGen/convertvector.c
@@ -9,14 +9,6 @@
 typedef unsigned short  vector8ushort  __attribute__((__vector_size__(16)));
 
 #ifdef __cplusplus
-#define BOOL bool
-#else
-#define BOOL _Bool
-#endif
-
-typedef BOOL vector8bool __attribute__((__ext_vector_type__(8)));
-
-#ifdef __cplusplus
 extern "C" {
 #endif
 
@@ -32,13 +24,6 @@
   // CHECK: fpext <8 x float> %{{[^ ]}} to <8 x double>
 }
 
-vector8bool flt_tobool(vector8float x) {
-  return __builtin_convertvector(x, vector8bool);
-  // CHECK-LABEL: @flt_tobool
-  // CHECK-NOT: fptoui <8 x float> %{{[^ ]}} to <8 x i1>
-  // CHECK: fcmp une <8 x float> %{{[^ ]}}, zeroinitializer
-}
-
 vector8long flt_tosi(vector8float x) {
   return __builtin_convertvector(x, vector8long);
   // CHECK-LABEL: @flt_tosi
@@ -69,13 +54,6 @@
   // CHECK: sext <8 x i16> %{{[^ ]}} to <8 x i64>
 }
 
-vector8bool int_tobool(vector8short x) {
-  return __builtin_convertvector(x, vector8bool);
-  // CHECK-LABEL: @int_tobool
-  // CHECK-NOT: trunc <8 x i16> %{{[^ ]}} to <8 x i1>
-  // CHECK: icmp ne <8 x i16> %{{[^ ]}}, zeroinitializer
-}
-
 vector8float int_tofp(vector8short x) {
   return __builtin_convertvector(x, vector8float);
   // CHECK-LABEL: @int_tofp
Index: lib/Sema/SemaType.cpp
===================================================================
--- lib/Sema/SemaType.cpp
+++ lib/Sema/SemaType.cpp
@@ -2183,10 +2183,16 @@
 /// Run the required checks for the extended vector type.
 QualType Sema::BuildExtVectorType(QualType T, Expr *ArraySize,
                                   SourceLocation AttrLoc) {
-  // unlike gcc's vector_size attribute, we do not allow vectors to be defined
+  // Unlike gcc's vector_size attribute, we do not allow vectors to be defined
   // in conjunction with complex types (pointers, arrays, functions, etc.).
-  if (!T->isDependentType() &&
-      !T->isIntegerType() && !T->isRealFloatingType()) {
+  //
+  // Additionally, OpenCL prohibits vectors of booleans (they're considered a
+  // reserved data type under OpenCL v2.0 s6.1.4), we don't support selects
+  // on bitvectors, and we have no well-defined ABI for bitvectors, so vectors
+  // of bool aren't allowed.
+  if ((!T->isDependentType() && !T->isIntegerType() &&
+       !T->isRealFloatingType()) ||
+      T->isBooleanType()) {
     Diag(AttrLoc, diag::err_attribute_invalid_vector_type) << T;
     return QualType();
   }
@@ -2200,7 +2206,7 @@
       return QualType();
     }
 
-    // unlike gcc's vector_size attribute, the size is specified as the
+    // Unlike gcc's vector_size attribute, the size is specified as the
     // number of elements, not the number of bytes.
     unsigned vectorSize = static_cast<unsigned>(vecSize.getZExtValue());
 


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