forked from OSchip/llvm-project
[DAGCombine] Enable more pre-indexed stores
The current check in CombineToPreIndexedLoadStore is too conversative, preventing a pre-indexed store when the base pointer is a predecessor of the value being stored. Instead, we should check the pointer operand of the store. Differential Revision: https://reviews.llvm.org/D56719 llvm-svn: 351933
This commit is contained in:
Sam Parker
parent
e70ba0a1bc
commit
9a2a89d58f
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@ -12652,7 +12652,13 @@ bool DAGCombiner::CombineToPreIndexedLoadStore(SDNode *N) {
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// Check #2.
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if (!isLoad) {
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SDValue Val = cast<StoreSDNode>(N)->getValue();
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if (Val == BasePtr || BasePtr.getNode()->isPredecessorOf(Val.getNode()))
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// Would require a copy.
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if (Val == BasePtr)
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return false;
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// Would create a cycle.
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if (Val == Ptr || Ptr->isPredecessorOf(Val.getNode()))
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return false;
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}
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@ -0,0 +1,186 @@
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; RUN: llc -mtriple=thumbv8m.main %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-V8M
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; RUN: llc -mtriple=armv8 %s -o - | FileCheck %s --check-prefix=CHECK-V8
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; CHECK-LABEL: pre_inc_ldr
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; CHECK: ldr{{.*}}, [r0, #4]!
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define i32* @pre_inc_ldr(i32* %base, i32 %a) {
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%addr = getelementptr i32, i32* %base, i32 1
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%ld = load i32, i32* %addr
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%addr.1 = getelementptr i32, i32* %base, i32 2
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%res = add i32 %ld, %a
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store i32 %res, i32* %addr.1
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ret i32* %addr
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}
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; CHECK-LABEL: pre_dec_ldr
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; CHECK: ldr{{.*}}, [r0, #-4]!
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define i32* @pre_dec_ldr(i32* %base, i32 %a) {
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%addr = getelementptr i32, i32* %base, i32 -1
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%ld = load i32, i32* %addr
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%addr.1 = getelementptr i32, i32* %base, i32 2
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%res = add i32 %ld, %a
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store i32 %res, i32* %addr.1
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ret i32* %addr
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}
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; CHECK-LABEL: post_inc_ldr
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; CHECK: ldr{{.*}}, [r0], #4
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define i32* @post_inc_ldr(i32* %base, i32* %addr.2, i32 %a) {
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%addr = getelementptr i32, i32* %base, i32 0
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%ld = load i32, i32* %addr
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%addr.1 = getelementptr i32, i32* %base, i32 1
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%res = add i32 %ld, %a
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store i32 %res, i32* %addr.2
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ret i32* %addr.1
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}
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; CHECK-LABEL: post_dec_ldr
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; CHECK: ldr{{.*}}, [r0], #-4
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define i32* @post_dec_ldr(i32* %base, i32* %addr.2, i32 %a) {
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%addr = getelementptr i32, i32* %base, i32 0
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%ld = load i32, i32* %addr
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%addr.1 = getelementptr i32, i32* %base, i32 -1
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%res = add i32 %ld, %a
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store i32 %res, i32* %addr.2
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ret i32* %addr.1
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}
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; CHECK-LABEL: pre_inc_str
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; CHECK: str{{.*}}, [r0, #4]!
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define i32* @pre_inc_str(i32* %base, i32 %a, i32 %b) {
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%addr.1 = getelementptr i32, i32* %base, i32 1
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%res = add i32 %a, %b
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store i32 %res, i32* %addr.1
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ret i32* %addr.1
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}
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; CHECK-LABEL: pre_dec_str
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; CHECK: str{{.*}}, [r0, #-4]!
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define i32* @pre_dec_str(i32* %base, i32 %a, i32 %b) {
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%res = add i32 %a, %b
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%addr.1 = getelementptr i32, i32* %base, i32 -1
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store i32 %res, i32* %addr.1
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ret i32* %addr.1
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}
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; CHECK-LABEL: post_inc_str
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; CHECK: str{{.*}}, [r0], #4
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define i32* @post_inc_str(i32* %base, i32 %a, i32 %b) {
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%addr.1 = getelementptr i32, i32* %base, i32 1
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%res = add i32 %a, %b
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store i32 %res, i32* %base
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ret i32* %addr.1
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}
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; CHECK-LABEL: post_dec_str
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; CHECK: str{{.*}}, [r0], #-4
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define i32* @post_dec_str(i32* %base, i32 %a, i32 %b) {
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%addr.1 = getelementptr i32, i32* %base, i32 -1
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%res = add i32 %a, %b
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store i32 %res, i32* %base
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ret i32* %addr.1
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}
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; TODO: Generate ldrd
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; CHECK-LABEL: pre_inc_ldrd
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; CHECK: ldr{{.*}}, #4]!
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define i32* @pre_inc_ldrd(i32* %base) {
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%addr = getelementptr i32, i32* %base, i32 1
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%addr.1 = getelementptr i32, i32* %base, i32 2
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%addr.2 = getelementptr i32, i32* %base, i32 3
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%ld = load i32, i32* %addr
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%ld.1 = load i32, i32* %addr.1
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%res = add i32 %ld, %ld.1
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store i32 %res, i32* %addr.2
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ret i32* %addr
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}
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; TODO: Generate ldrd
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; CHECK-LABEL: pre_dec_ldrd
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; CHECK: ldr{{.*}}, #-4]!
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define i32* @pre_dec_ldrd(i32* %base) {
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%addr = getelementptr i32, i32* %base, i32 -1
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%addr.1 = getelementptr i32, i32* %base, i32 -2
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%addr.2 = getelementptr i32, i32* %base, i32 -3
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%ld = load i32, i32* %addr
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%ld.1 = load i32, i32* %addr.1
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%res = add i32 %ld, %ld.1
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store i32 %res, i32* %addr.2
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ret i32* %addr
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}
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; TODO: Generate post inc
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; CHECK-LABEL: post_inc_ldrd
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; CHECK-V8M: ldrd{{.*}}, [r0]
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; CHECK-V8: ldm
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; CHECK: add{{.*}}, #8
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define i32* @post_inc_ldrd(i32* %base, i32* %addr.3) {
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%addr = getelementptr i32, i32* %base, i32 0
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%ld = load i32, i32* %addr
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%addr.1 = getelementptr i32, i32* %base, i32 1
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%ld.1 = load i32, i32* %addr.1
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%addr.2 = getelementptr i32, i32* %base, i32 2
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%res = add i32 %ld, %ld.1
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store i32 %res, i32* %addr.3
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ret i32* %addr.2
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}
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; CHECK-LABEL: pre_inc_str_multi
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; CHECK: str{{.*}}, #8]!
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define i32* @pre_inc_str_multi(i32* %base) {
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%addr = getelementptr i32, i32* %base, i32 0
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%addr.1 = getelementptr i32, i32* %base, i32 1
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%ld = load i32, i32* %addr
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%ld.1 = load i32, i32* %addr.1
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%res = add i32 %ld, %ld.1
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%addr.2 = getelementptr i32, i32* %base, i32 2
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store i32 %res, i32* %addr.2
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ret i32* %addr.2
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}
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; CHECK-LABEL: pre_dec_str_multi
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; CHECK: str{{.*}}, #-4]!
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define i32* @pre_dec_str_multi(i32* %base) {
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%addr = getelementptr i32, i32* %base, i32 0
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%addr.1 = getelementptr i32, i32* %base, i32 1
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%ld = load i32, i32* %addr
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%ld.1 = load i32, i32* %addr.1
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%res = add i32 %ld, %ld.1
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%addr.2 = getelementptr i32, i32* %base, i32 -1
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store i32 %res, i32* %addr.2
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ret i32* %addr.2
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}
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; CHECK-LABEL: illegal_pre_inc_store_1
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; CHECK-NOT: str{{.*}} ]!
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define i32* @illegal_pre_inc_store_1(i32* %base) {
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entry:
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%ptr.to.use = getelementptr i32, i32* %base, i32 2
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%ptr.to.store = ptrtoint i32* %base to i32
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store i32 %ptr.to.store, i32* %ptr.to.use, align 4
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ret i32* %ptr.to.use
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}
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; TODO: The mov should be unecessary
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; CHECK-LABEL: legal_pre_inc_store_needs_copy_1
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; CHECK: add{{.*}}, #8
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; CHECK-NOT: str{{.*}}]!
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; CHECK: mov
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define i32* @legal_pre_inc_store_needs_copy_1(i32* %base) {
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entry:
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%ptr.to.use = getelementptr i32, i32* %base, i32 2
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%ptr.to.store = ptrtoint i32* %ptr.to.use to i32
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store i32 %ptr.to.store, i32* %ptr.to.use, align 4
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ret i32* %ptr.to.use
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}
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; CHECK-LABEL: legal_pre_inc_store_needs_copy_2
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; CHECK-NOT: mov
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; CHECK-NOT: str{{.*}}]!
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define i32* @legal_pre_inc_store_needs_copy_2(i32 %base) {
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entry:
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%ptr = inttoptr i32 %base to i32*
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%ptr.to.use = getelementptr i32, i32* %ptr, i32 2
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store i32 %base, i32* %ptr.to.use, align 4
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ret i32* %ptr.to.use
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}
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