[llvm] r183238 - ARM: Fix crash in ARM backend inside of ARMConstantIslandPass

[David Majnemer]

Presumably for the same reason why we use ldr for 'ptrtoint (i32* @a to
i32)' instead of movw/movt. Why do you ask? Do you think using ldrb is
incorrect?

-- 
David Majnemer


On Tue, Jun 4, 2013 at 5:43 PM, JF Bastien <jfb at google.com> wrote:

> I'm not sure I understand: why is it that ldrb ever gets emitted instead
> of movs with immediate?
>
>
> On Tue, Jun 4, 2013 at 10:46 AM, David Majnemer <david.majnemer at gmail.com>wrote:
>
>> Author: majnemer
>> Date: Tue Jun  4 12:46:15 2013
>> New Revision: 183238
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=183238&view=rev
>> Log:
>> ARM: Fix crash in ARM backend inside of ARMConstantIslandPass
>>
>> The ARM backend did not expect LDRBi12 to hold a constant pool operand.
>> Allow for LLVM to deal with the instruction similar to how it deals with
>> LDRi12.
>>
>> This fixes PR16215.
>>
>> Added:
>>     llvm/trunk/test/CodeGen/ARM/load-address-masked.ll
>> Modified:
>>     llvm/trunk/lib/Target/ARM/ARMConstantIslandPass.cpp
>>
>> Modified: llvm/trunk/lib/Target/ARM/ARMConstantIslandPass.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMConstantIslandPass.cpp?rev=183238&r1=183237&r2=183238&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/Target/ARM/ARMConstantIslandPass.cpp (original)
>> +++ llvm/trunk/lib/Target/ARM/ARMConstantIslandPass.cpp Tue Jun  4
>> 12:46:15 2013
>> @@ -753,6 +753,7 @@ initializeFunctionInfo(const std::vector
>>              Scale = 4;
>>              break;
>>
>> +          case ARM::LDRBi12:
>>            case ARM::LDRi12:
>>            case ARM::LDRcp:
>>            case ARM::t2LDRpci:
>>
>> Added: llvm/trunk/test/CodeGen/ARM/load-address-masked.ll
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/load-address-masked.ll?rev=183238&view=auto
>>
>> ==============================================================================
>> --- llvm/trunk/test/CodeGen/ARM/load-address-masked.ll (added)
>> +++ llvm/trunk/test/CodeGen/ARM/load-address-masked.ll Tue Jun  4
>> 12:46:15 2013
>> @@ -0,0 +1,14 @@
>> +; RUN: llc < %s -mtriple=armv4t-unknown-linux-gnueabi
>> -verify-machineinstrs | FileCheck %s
>> +
>> +target datalayout =
>> "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:64:128-a0:0:64-n32-S64"
>> +target triple = "armv4t-unknown-linux-gnueabi"
>> +
>> + at a = global i32 0, align 4
>> +
>> +define i32 @foo() {
>> +entry:
>> +  ret i32 and (i32 ptrtoint (i32* @a to i32), i32 255)
>> +}
>> +
>> +; CHECK: foo:
>> +; CHECK: ldrb    r0, .LCPI0_0
>>
>>
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>>
>
>
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