[PATCH] D25866: [Sema] Support implicit scalar to vector conversions

[Bruno Cardoso Lopes via cfe-commits]

bruno added a comment.

Hi,

Nice, thanks for working on this!



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Comment at: lib/Sema/SemaExpr.cpp:8051
+  if (!LHSVecType) {
+    assert(RHSVecType && "RHSVecType is not a vector!");
     if (!tryVectorConvertAndSplat(*this, (IsCompAssign ? nullptr : &LHS),
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`tryVectorConvertAndSplat` does more than plain scalar splat; it supports a more general type of CK_IntegralCast, see the comment on one of your changes to the tests below.

I suggest that instead of reusing this function, you should create another one that only handles the cases we actually want to support for non-ext vectors (i.e. for GCC compat). 


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Comment at: test/Sema/vector-cast.c:57
+  // FIXME: This lacks a diagnostic: should complain that 'double' to vector 'float2' involves truncation
+  f2 += d;
+  d += f2; // expected-error {{assigning to 'double' from incompatible type 'float2' (vector of 2 'float' values)}}
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This is not right. The fact that we don't have the appropriate diagnostics here doesn't mean we should accept this. For instance, this is what we get with GCC:

error: conversion of scalar 'double' to vector 'float2 {aka __vector(2) float}' involves truncation


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Comment at: test/Sema/vector-scalar-implict-conv.c:2
+// RUN: %clang_cc1 %s -verify -fsyntax-only -Weverything
+
+typedef long long v2i64 __attribute__((vector_size(16)));
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Can you rename this to vector-gcc-compat.c? It would also be nice to split functionality being tested within their own function, e.g.: arithmetic, logic, vector comparisons.


https://reviews.llvm.org/D25866