[llvm-dev] Error in v64i32 type in x86 backend

[hameeza ahmed via llvm-dev]

Please correct me i m stuck at this point.

On Jul 6, 2017 5:18 PM, "hameeza ahmed" <hahmed2305 at gmail.com> wrote:

Hello,
i am experimenting with the increase in register/ vector width to 64
elements of 32 bits instead of 16 in x86 backend.
for eg.
i have a loop with 65 iterations;
if my IR generates v64i32 and 1 scalar, still the backend breaks the v64i32
into 4 v16i32. i want it to retain v64i32. like if there are 128 elements
in loop then it should break it into 2 v64i32 instructions.

in order to do this i have made necessary changes in X86ISelLowering.cpp.
and rebuild llvm. then when i use the command -view-dag-combine2-dags i get
the required output in graph but the following error on console:

LLVM ERROR: Cannot select: t10: ch = store<ST256[bitcast ([65 x i32]* @a to
<64 x i32>*)](align=16)(tbaa=<0x30c5438>)> t9, t7, t12, undef:i64
  t7: v64i32 = add t6, t4
    t6: v64i32,ch = load<LD256[bitcast ([65 x i32]* @c to <64 x
i32>*)](align=16)(tbaa=<0x30c5438>)(dereferenceable)> t0, t14, undef:i64
      t14: i64 = X86ISD::Wrapper TargetGlobalAddress:i64<[65 x i32]* @c> 0
        t13: i64 = TargetGlobalAddress<[65 x i32]* @c> 0
      t3: i64 = undef
    t4: v64i32,ch = load<LD256[bitcast ([65 x i32]* @b to <64 x
i32>*)](align=16)(tbaa=<0x30c5438>)(dereferenceable)> t0, t16, undef:i64
      t16: i64 = X86ISD::Wrapper TargetGlobalAddress:i64<[65 x i32]* @b> 0
        t15: i64 = TargetGlobalAddress<[65 x i32]* @b> 0
      t3: i64 = undef
  t12: i64 = X86ISD::Wrapper TargetGlobalAddress:i64<[65 x i32]* @a> 0
    t11: i64 = TargetGlobalAddress<[65 x i32]* @a> 0
  t3: i64 = undef
In function: foo

The dag after legalization is also attached here.

the source is vector sum of 65 elements.


Kindly correct me.
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