opt: Rename -default-data-layout flag to -data-layout and make it always override the layout.

There isn't much point in a flag that only works if the data layout is empty.

Differential Revision: https://reviews.llvm.org/D30014

llvm-svn: 295468
diff --git a/llvm/test/Transforms/ConstProp/loads.ll b/llvm/test/Transforms/ConstProp/loads.ll
index 89387ad..dce2068 100644
--- a/llvm/test/Transforms/ConstProp/loads.ll
+++ b/llvm/test/Transforms/ConstProp/loads.ll
@@ -1,5 +1,5 @@
-; RUN: opt < %s -default-data-layout="e-p:64:64:64-p1:16:16:16-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64" -instcombine -S | FileCheck %s --check-prefix=LE
-; RUN: opt < %s -default-data-layout="E-p:64:64:64-p1:16:16:16-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64" -instcombine -S | FileCheck %s --check-prefix=BE
+; RUN: opt < %s -data-layout="e-p:64:64:64-p1:16:16:16-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64" -instcombine -S | FileCheck %s --check-prefix=LE
+; RUN: opt < %s -data-layout="E-p:64:64:64-p1:16:16:16-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64" -instcombine -S | FileCheck %s --check-prefix=BE
 
 ; {{ 0xDEADBEEF, 0xBA }, 0xCAFEBABE}
 @g1 = constant {{i32,i8},i32} {{i32,i8} { i32 -559038737, i8 186 }, i32 -889275714 }