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TableGen: Change { } to only accept bits<n> entries when n == 1.

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Prior to this change, it was legal to do something like

  bits<2> opc = { 0, 1 };
  bits<2> opc2 = { 1, 0 };
  bits<2> a = { opc, opc2 };

This involved silently dropping bits from opc and opc2 which is very hard to debug.

Now the above test would be an error.  Having tested with an assert, none of LLVM/clang was relying on this behaviour.

Thanks to Adam Nemet for the above test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215083 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Pete Cooper 2014-08-07 05:46:57 +00:00
parent 3f2aee7e02
commit f5b7351124
2 changed files with 26 additions and 1 deletions
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5
lib/TableGen/Record.cpp
View File

@ -114,8 +114,11 @@ Init *BitRecTy::convertValue(IntInit *II) {
Init *BitRecTy::convertValue(TypedInit *VI) {
RecTy *Ty = VI->getType();
if (isa<BitRecTy>(Ty) || isa<BitsRecTy>(Ty) || isa<IntRecTy>(Ty))
if (isa<BitRecTy>(Ty))
return VI; // Accept variable if it is already of bit type!
if (auto *BitsTy = dyn_cast<BitsRecTy>(Ty))
// Accept only bits<1> expression.
return BitsTy->getNumBits() == 1 ? VI : nullptr;
return nullptr;
}

22
test/TableGen/BitsInit.td Normal file
View File

@ -0,0 +1,22 @@
// RUN: not llvm-tblgen %s 2>&1 > %t
// RUN: FileCheck %s < %t
def a {
bits<2> opc = { 0, 1 };
bits<2> opc2 = { 1, 0 };
bits<1> opc3 = { 1 };
bits<2> a = { opc, opc2 }; // error!
bits<2> b = { opc{0}, opc2{0} };
bits<2> c = { opc{1}, opc2{1} };
bits<2> c = { opc3{0}, opc3 };
}
// CHECK: def a {
// CHECK: bits<2> opc = { 0, 1 };
// CHECK: bits<2> opc2 = { 1, 0 };
// CHECK: bits<1> opc3 = { 1 };
// CHECK: bits<2> a = { ?, ? };
// CHECK: bits<2> b = { 1, 0 };
// CHECK: bits<2> c = { 1, 1 };
// CHECK: }