================
@@ -19,17 +19,21 @@ extern "C" void construct() {
WithCtor c(2,5);
}
-// CIR: cir.global "private" constant cir_private @__const.construct.c =
#cir.const_record<{#cir.int<4> : !s32i, #cir.zero : !cir.array<!u8i x 4>,
#cir.int<10> : !s64i, #cir.const_record<{#cir.int<5> : !s32i}> : !rec_HasVal,
#cir.zero : !cir.array<!u8i x 4>}> : !rec_WithCtor
+// CIR: cir.global "private" constant cir_private @__const.construct.tmp =
#cir.const_record<{#cir.int<4> : !s32i, #cir.zero : !cir.array<!u8i x 4>,
#cir.int<10> : !s64i, #cir.const_record<{#cir.int<5> : !s32i}> : !rec_HasVal,
#cir.zero : !cir.array<!u8i x 4>}> : !rec_WithCtor
// CIR-LABEL: construct()
// CIR-NEXT: %[[WC_ALLOCA:.*]] = cir.alloca "c" {{.*}} :
!cir.ptr<!rec_WithCtor>
-// CIR-NEXT: %[[GET_GLOBAL:.*]] = cir.get_global @__const.construct.c :
!cir.ptr<!rec_WithCtor>
-// CIR-NEXT: cir.copy %[[GET_GLOBAL]] align(8) to %[[WC_ALLOCA]] align(8) :
!cir.ptr<!rec_WithCtor>
+// CIR-NEXT: %[[TMP_ALLOCA:.*]] = cir.alloca "tmp" {{.*}} :
!cir.ptr<!rec_WithCtor>
+// CIR-NEXT: %[[GET_GLOBAL:.*]] = cir.get_global @__const.construct.tmp :
!cir.ptr<!rec_WithCtor>
+// CIR-NEXT: cir.copy %[[GET_GLOBAL]] align(8) to %[[TMP_ALLOCA]] align(8) :
!cir.ptr<!rec_WithCtor>
+// CIR-NEXT: cir.copy %[[TMP_ALLOCA]] align(8) to %[[WC_ALLOCA]] align(8)
skip_tail_padding : !cir.ptr<!rec_WithCtor>
// CIR-NEXT: cir.return
-// LLVM: @__const.construct.c = private constant %struct.WithCtor <{ i32 4, [4
x i8] zeroinitializer, i64 10, %struct.HasVal { i32 5 }, [4 x i8]
zeroinitializer }>
+// LLVM: @__const.construct.tmp = private constant %struct.WithCtor <{ i32 4,
[4 x i8] zeroinitializer, i64 10, %struct.HasVal { i32 5 }, [4 x i8]
zeroinitializer }>
// LLVM-LABEL: construct()
// LLVM-NEXT: %[[WC_ALLOCA:.*]] = alloca %struct.WithCtor
-// LLVM-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 8 %1, ptr align 8
@__const.construct.c, i64 24, i1 false)
+// LLVM-NEXT: %[[TMP_ALLOCA:.*]] = alloca %struct.WithCtor
+// LLVM-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 8 %[[TMP_ALLOCA]],
ptr align 8 @__const.construct.tmp, i64 24, i1 false)
+// LLVM-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 8 %[[WC_ALLOCA]], ptr
align 8 %[[TMP_ALLOCA]], i64 20, i1 false)
----------------
erichkeane wrote:
Classic codegen only does the 'init the whole thing' (we are doing memcpy
because we have a global with the value, rather than element-wise init'ing it)
when it is a constant-aggregate, which it doesn't do here because of the
constructor (it is set on 'isPOD' which isn't really accurate anymore, but
reasonably so?).
So it falls back to element-wise init, which LLVM then seems to const-ify.
So just a case of CIR being 'better' at detecting when it can do a memcpy that
classic codegen never bothered to do.
https://github.com/llvm/llvm-project/pull/229478
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