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llvm-mirror/test/CodeGen/ARM/memcpy-const-vol-struct.ll
Simon Wallis 63f9b9c858 [SelectionDAG] memcpy expansion of const volatile struct ignores const zero
In getMemcpyLoadsAndStores(), a memcpy where the source is a zero constant is expanded to a MemOp::Set instead of a MemOp::Copy, even when the memcpy is volatile.
This is incorrect.

The fix is to add a check for volatile, and expand to MemOp::Copy in the volatile case.

Reviewed By: chill

Differential Revision: https://reviews.llvm.org/D87134
2020-09-07 13:22:09 +01:00

19 lines
740 B
LLVM

; RUN: llc -mtriple=armv7-arm-none-eabi -o - %s | FileCheck %s
%struct.sMyType = type { i32 }
@val = hidden constant %struct.sMyType zeroinitializer, align 4
@v = internal global %struct.sMyType zeroinitializer, align 4
define hidden void @InitVal() local_unnamed_addr {
entry:
call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 bitcast (%struct.sMyType* @v to i8*), i8* align 4 bitcast (%struct.sMyType* @val to i8*), i32 4, i1 true)
; The last argument is the isvolatile argument. This is a volatile memcpy.
; Test that the memcpy expansion does not optimize away the load.
; CHECK: ldr
; CHECK: str
ret void
}
declare void @llvm.memcpy.p0i8.p0i8.i32(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i32, i1 immarg)