http://llvm.org/bugs/show_bug.cgi?id=9370
Summary: [arm] unnecessary MOVW not optimized
Product: libraries
Version: trunk
Platform: PC
OS/Version: Linux
Status: NEW
Severity: enhancement
Priority: P
Component: Backend: ARM
AssignedTo: [email protected]
ReportedBy: [email protected]
CC: [email protected]
this:
volatile store i32 -1, i32* inttoptr (i32 1342210076 to i32*), align 4, !tbaa
!0
volatile store i32 -1, i32* inttoptr (i32 1342341148 to i32*), align 4, !tbaa
!0
is compiled and optimized to that:
movw r0, #32796
mov.w r1, #-1
movt r0, #20480
str r1, [r0]
movw r0, #32796 @ <= this MOVW is not needed, value is there already
movt r0, #20482
str r1, [r0]
the initial C code was:
LPC_GPIO0->IC = ~0;
LPC_GPIO2->IC = ~0;
It was compiled with -march=thumb -mcpu=cortex-m3 -O3
btw: Thanks for the great work, the ARM code looks quite good already!
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