Renato Golin abc00cb813 [ARM] Support and tests for transform of LDR rt, = to MOV ...

This change implements the transformation in processInstruction() for the
LDR rt, =expression to MOV rt, expression when the expression can be evaluated
and can fit into the immediate field of the MOV or a MVN.

Across the ARM and Thumb instruction sets there are several cases to consider,
each with a different range of representatble constants.

In ARM we have:
 * Modified immediate (All ARM architectures)
 * MOVW (v6t2 and above)

In Thumb we have:
 * Modified immediate (v6t2, v7m and v8m.mainline)
 * MOVW (v6t2, v7m, v8.mainline and v8m.baseline)
 * Narrow Thumb MOV that can be used in an IT block (non flag-setting)

If the immediate fits any of the available alternatives then we make the transformation.

Fixes 25722.

Patch by Peter Smith.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269354 91177308-0d34-0410-b5e6-96231b3b80d8

2016-05-12 21:22:42 +00:00

..

ARMAsmParser.cpp

[ARM] Support and tests for transform of LDR rt, = to MOV

2016-05-12 21:22:42 +00:00

CMakeLists.txt

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LLVMBuild.txt

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