[array_ref hack] llvm-gcc abort on tricky VLA cast

[sunfishcode]

Bugzilla Link	2175
Resolution	WONTFIX
Resolved on	Dec 02, 2010 01:58
Version	trunk
OS	All
CC	@asl,@efriedma-quic

Extended Description

llvm-gcc aborts on this:

void *p(void);
long d(void);

float foo(long i0, long i1, long i2, long i3, long i4, long i5) {
return ((float (((*)[d()])[])[])p())[i0][i1][i2][i3][i4][i5];
}

The abort looks like this:

Unhandled expression!
TREE_CODE: 117
<save_expr 0x41d14990
type <integer_type 0x41d0c3f0 long int public SI
size <integer_cst 0x41d046c0 constant invariant 32>
unit size <integer_cst 0x41d041e0 constant invariant 4>
align 32 symtab 2 alias set -1 precision 32 min <integer_cst 0x41d047e0 -2147483648> max <integer_cst 0x41d04810 2147483647>
LLVM: i32
pointer_to_this <pointer_type 0x41d16b60>>
side-effects invariant
arg 0 <call_expr 0x41d14900 type <integer_type 0x41d0c3f0 long int>
side-effects
arg 0 <addr_expr 0x41d148d0 type <pointer_type 0x41dbacb0>
constant invariant arg 0 <function_decl 0x41dbb300 d>>>>
t.c: In function ‘foo’:
t.c:4: internal compiler error: in Emit, at llvm-convert.cpp:851

[llvmbot]

I think this is yet another example of the "array-ref hack"
causing trouble (this is a trick used to get better code).
With gcc-4.2 I get:

$ gcc -S pr2175.c
pr2175.c: In function ‘foo’:
pr2175.c:5: error: invalid use of array with unspecified bounds
pr2175.c:5: error: invalid use of array with unspecified bounds

[lattner]

*** Bug llvm/llvm-bugzilla-archive#3249 has been marked as a duplicate of this bug. ***

[lattner]

I have no plan to fix this.

[llvmbot]

gcc-4.5 refuses to compile this, so not an issue for dragonegg.

[lattner]

mentioned in issue llvm/llvm-bugzilla-archive#3249