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nate-chandlernate-chandler
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Merge pull request #82784 from nate-chandler/rdar153693915
[Mem2Reg] Don't promote proj(unchecked_addr_cast).
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‎lib/SILOptimizer/Transforms/SILMem2Reg.cpp

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Original file line numberDiff line numberDiff line change
@@ -438,6 +438,16 @@ static bool isAddressForLoad(SILInstruction *load, SILBasicBlock *&singleBlock,
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!isa<TupleElementAddrInst>(load))
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return false;
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// In OSSA, the result of an unchecked_bitwise_cast must immediately be
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// copied or unchecked_bitwise_cast'd again. In particular, it is not
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// permitted to borrow it and perform additional projections (struct_extract,
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// tuple_extract) on the borrowed value. Consequently, we cannot promote an
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// address if such a promotion would result in such a pattern.
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if (load->getFunction()->hasOwnership() &&
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isa<UncheckedAddrCastInst>(load->getOperand(0)) &&
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!isa<UncheckedAddrCastInst>(load))
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return false;
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// None of the projections are lowered to owned values:
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//
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// struct_element_addr and tuple_element_addr instructions are lowered to

‎test/SILOptimizer/mem2reg.sil

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@@ -29,6 +29,24 @@ struct Pair<T, U> {
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var u: U
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}
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class C {}
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struct J {
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var c: C
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}
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struct I {
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var j: J
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}
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struct S1 {
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var i: I
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}
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struct S2 {
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var t: (J, J)
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}
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///////////
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// Tests //
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///////////
@@ -578,3 +596,60 @@ bb0:
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dealloc_stack %11 : $*Pair<T, ()>
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return undef : $()
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}
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// CHECK-LABEL: sil @promo_proj_uac_1 : {{.*}} {
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// CHECK-NOT: alloc_stack
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// CHECK-LABEL: } // end sil function 'promo_proj_uac_1'
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sil @promo_proj_uac_1 : $@convention(thin) () -> () {
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bb0:
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%s = apply undef() : $@convention(thin) () -> (@owned S1)
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%addr = alloc_stack $S1
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store %s to %addr
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%i_addr = unchecked_addr_cast %addr to $*I
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%j_addr = struct_element_addr %i_addr, #I.j
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%j = load %j_addr
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retain_value %j
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destroy_addr %addr
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dealloc_stack %addr
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apply undef(%j) : $@convention(thin) (@owned J) -> ()
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%retval = tuple ()
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return %retval
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}
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// CHECK-LABEL: sil @promo_proj_uac_2 : {{.*}} {
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// CHECK-NOT: alloc_stack
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// CHECK-LABEL: } // end sil function 'promo_proj_uac_2'
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sil @promo_proj_uac_2 : $@convention(thin) () -> () {
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bb0:
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%s = apply undef() : $@convention(thin) () -> (@owned S2)
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%addr = alloc_stack $S2
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store %s to %addr
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%t_addr = unchecked_addr_cast %addr to $*(J, J)
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%j_addr = tuple_element_addr %t_addr, 0
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%j = load %j_addr
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retain_value %j
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destroy_addr %addr
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dealloc_stack %addr
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apply undef(%j) : $@convention(thin) (@owned J) -> ()
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%retval = tuple ()
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return %retval
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}
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// CHECK-LABEL: sil @promo_proj_uac_3 : {{.*}} {
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// CHECK-NOT: alloc_stack
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// CHECK-LABEL: } // end sil function 'promo_proj_uac_3'
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sil @promo_proj_uac_3 : $@convention(thin) () -> () {
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bb0:
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%s = apply undef() : $@convention(thin) () -> (@owned S1)
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%addr = alloc_stack $S1
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store %s to %addr
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%i_addr = unchecked_addr_cast %addr to $*I
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%j_addr = unchecked_addr_cast %i_addr to $*J
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%j = load %j_addr
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retain_value %j
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destroy_addr %addr
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dealloc_stack %addr
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apply undef(%j) : $@convention(thin) (@owned J) -> ()
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%retval = tuple ()
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return %retval
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}

‎test/SILOptimizer/mem2reg_ossa.sil

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Original file line numberDiff line numberDiff line change
@@ -46,6 +46,22 @@ struct S {
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var field: C
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}
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struct J {
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var c: C
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}
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struct I {
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var j: J
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}
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struct S1 {
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var i: I
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}
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struct S2 {
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var t: (J, J)
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}
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///////////
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// Tests //
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///////////
@@ -761,3 +777,57 @@ entry(%instance : @owned $C):
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%retval = tuple ()
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return %retval : $()
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}
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// CHECK-LABEL: sil [ossa] @no_promo_proj_uac_1 : {{.*}} {
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// CHECK: alloc_stack
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// CHECK-LABEL: } // end sil function 'no_promo_proj_uac_1'
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sil [ossa] @no_promo_proj_uac_1 : $@convention(thin) () -> () {
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bb0:
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%s = apply undef() : $@convention(thin) () -> (@owned S1)
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%addr = alloc_stack $S1
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store %s to [init] %addr
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%i_addr = unchecked_addr_cast %addr to $*I
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%j_addr = struct_element_addr %i_addr, #I.j
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%j = load [copy] %j_addr
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destroy_addr %addr
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dealloc_stack %addr
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apply undef(%j) : $@convention(thin) (@owned J) -> ()
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%retval = tuple ()
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return %retval
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}
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// CHECK-LABEL: sil [ossa] @no_promo_proj_uac_2 : {{.*}} {
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// CHECK: alloc_stack
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// CHECK-LABEL: } // end sil function 'no_promo_proj_uac_2'
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sil [ossa] @no_promo_proj_uac_2 : $@convention(thin) () -> () {
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bb0:
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%s = apply undef() : $@convention(thin) () -> (@owned S2)
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%addr = alloc_stack $S2
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store %s to [init] %addr
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%t_addr = unchecked_addr_cast %addr to $*(J, J)
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%j_addr = tuple_element_addr %t_addr, 0
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%j = load [copy] %j_addr
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destroy_addr %addr
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dealloc_stack %addr
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apply undef(%j) : $@convention(thin) (@owned J) -> ()
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%retval = tuple ()
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return %retval
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}
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// CHECK-LABEL: sil [ossa] @promo_uac_uac : {{.*}} {
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// CHECK-NOT: alloc_stack
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// CHECK-LABEL: } // end sil function 'promo_uac_uac'
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sil [ossa] @promo_uac_uac : $@convention(thin) () -> () {
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bb0:
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%s = apply undef() : $@convention(thin) () -> (@owned S1)
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%addr = alloc_stack $S1
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store %s to [init] %addr
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%i_addr = unchecked_addr_cast %addr to $*I
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%j_addr = unchecked_addr_cast %i_addr to $*J
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%j = load [copy] %j_addr
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destroy_addr %addr
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dealloc_stack %addr
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apply undef(%j) : $@convention(thin) (@owned J) -> ()
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%retval = tuple ()
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return %retval
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}

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