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			524 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			LLVM
		
	
	
	
	
	
|   | ; RUN: opt < %s -basicaa -dse -S | FileCheck %s
 | ||
|  | ; RUN: opt < %s -aa-pipeline=basic-aa -passes=dse -S | FileCheck %s
 | ||
|  | target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128" | ||
|  | 
 | ||
|  | declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) nounwind | ||
|  | declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind | ||
|  | declare void @llvm.init.trampoline(i8*, i8*, i8*) | ||
|  | 
 | ||
|  | define void @test1(i32* %Q, i32* %P) { | ||
|  |         %DEAD = load i32, i32* %Q | ||
|  |         store i32 %DEAD, i32* %P | ||
|  |         store i32 0, i32* %P | ||
|  |         ret void | ||
|  | ; CHECK-LABEL: @test1(
 | ||
|  | ; CHECK-NEXT: store i32 0, i32* %P
 | ||
|  | ; CHECK-NEXT: ret void
 | ||
|  | } | ||
|  | 
 | ||
|  | ; PR8576 - Should delete store of 10 even though p/q are may aliases.
 | ||
|  | define void @test2(i32 *%p, i32 *%q) { | ||
|  |   store i32 10, i32* %p, align 4 | ||
|  |   store i32 20, i32* %q, align 4 | ||
|  |   store i32 30, i32* %p, align 4 | ||
|  |   ret void | ||
|  | ; CHECK-LABEL: @test2(
 | ||
|  | ; CHECK-NEXT: store i32 20
 | ||
|  | } | ||
|  | 
 | ||
|  | 
 | ||
|  | ; PR8677
 | ||
|  | @g = global i32 1 | ||
|  | 
 | ||
|  | define i32 @test3(i32* %g_addr) nounwind { | ||
|  | ; CHECK-LABEL: @test3(
 | ||
|  | ; CHECK: load i32, i32* %g_addr
 | ||
|  |   %g_value = load i32, i32* %g_addr, align 4 | ||
|  |   store i32 -1, i32* @g, align 4 | ||
|  |   store i32 %g_value, i32* %g_addr, align 4 | ||
|  |   %tmp3 = load i32, i32* @g, align 4 | ||
|  |   ret i32 %tmp3 | ||
|  | } | ||
|  | 
 | ||
|  | 
 | ||
|  | define void @test4(i32* %Q) { | ||
|  |         %a = load i32, i32* %Q | ||
|  |         store volatile i32 %a, i32* %Q | ||
|  |         ret void | ||
|  | ; CHECK-LABEL: @test4(
 | ||
|  | ; CHECK-NEXT: load i32
 | ||
|  | ; CHECK-NEXT: store volatile
 | ||
|  | ; CHECK-NEXT: ret void
 | ||
|  | } | ||
|  | 
 | ||
|  | define void @test5(i32* %Q) { | ||
|  |         %a = load volatile i32, i32* %Q | ||
|  |         store i32 %a, i32* %Q | ||
|  |         ret void | ||
|  | ; CHECK-LABEL: @test5(
 | ||
|  | ; CHECK-NEXT: load volatile
 | ||
|  | ; CHECK-NEXT: ret void
 | ||
|  | } | ||
|  | 
 | ||
|  | ; Should delete store of 10 even though memset is a may-store to P (P and Q may
 | ||
|  | ; alias).
 | ||
|  | define void @test6(i32 *%p, i8 *%q) { | ||
|  |   store i32 10, i32* %p, align 4       ;; dead.
 | ||
|  |   call void @llvm.memset.p0i8.i64(i8* %q, i8 42, i64 900, i32 1, i1 false) | ||
|  |   store i32 30, i32* %p, align 4 | ||
|  |   ret void | ||
|  | ; CHECK-LABEL: @test6(
 | ||
|  | ; CHECK-NEXT: call void @llvm.memset
 | ||
|  | } | ||
|  | 
 | ||
|  | ; Should delete store of 10 even though memcpy is a may-store to P (P and Q may
 | ||
|  | ; alias).
 | ||
|  | define void @test7(i32 *%p, i8 *%q, i8* noalias %r) { | ||
|  |   store i32 10, i32* %p, align 4       ;; dead.
 | ||
|  |   call void @llvm.memcpy.p0i8.p0i8.i64(i8* %q, i8* %r, i64 900, i32 1, i1 false) | ||
|  |   store i32 30, i32* %p, align 4 | ||
|  |   ret void | ||
|  | ; CHECK-LABEL: @test7(
 | ||
|  | ; CHECK-NEXT: call void @llvm.memcpy
 | ||
|  | } | ||
|  | 
 | ||
|  | ; Do not delete stores that are only partially killed.
 | ||
|  | define i32 @test8() { | ||
|  |         %V = alloca i32 | ||
|  |         store i32 1234567, i32* %V | ||
|  |         %V2 = bitcast i32* %V to i8* | ||
|  |         store i8 0, i8* %V2 | ||
|  |         %X = load i32, i32* %V | ||
|  |         ret i32 %X | ||
|  |          | ||
|  | ; CHECK-LABEL: @test8(
 | ||
|  | ; CHECK: store i32 1234567
 | ||
|  | } | ||
|  | 
 | ||
|  | 
 | ||
|  | ; Test for byval handling.
 | ||
|  | %struct.x = type { i32, i32, i32, i32 } | ||
|  | define void @test9(%struct.x* byval  %a) nounwind  { | ||
|  | 	%tmp2 = getelementptr %struct.x, %struct.x* %a, i32 0, i32 0 | ||
|  | 	store i32 1, i32* %tmp2, align 4 | ||
|  | 	ret void | ||
|  | ; CHECK-LABEL: @test9(
 | ||
|  | ; CHECK-NEXT: ret void
 | ||
|  | } | ||
|  | 
 | ||
|  | ; Test for inalloca handling.
 | ||
|  | define void @test9_2(%struct.x* inalloca  %a) nounwind  { | ||
|  | 	%tmp2 = getelementptr %struct.x, %struct.x* %a, i32 0, i32 0 | ||
|  | 	store i32 1, i32* %tmp2, align 4 | ||
|  | 	ret void | ||
|  | ; CHECK-LABEL: @test9_2(
 | ||
|  | ; CHECK-NEXT: ret void
 | ||
|  | } | ||
|  | 
 | ||
|  | ; va_arg has fuzzy dependence, the store shouldn't be zapped.
 | ||
|  | define double @test10(i8* %X) { | ||
|  |         %X_addr = alloca i8* | ||
|  |         store i8* %X, i8** %X_addr | ||
|  |         %tmp.0 = va_arg i8** %X_addr, double | ||
|  |         ret double %tmp.0 | ||
|  | ; CHECK-LABEL: @test10(
 | ||
|  | ; CHECK: store
 | ||
|  | } | ||
|  | 
 | ||
|  | 
 | ||
|  | ; DSE should delete the dead trampoline.
 | ||
|  | declare void @test11f() | ||
|  | define void @test11() { | ||
|  | ; CHECK-LABEL: @test11(
 | ||
|  | 	%storage = alloca [10 x i8], align 16		; <[10 x i8]*> [#uses=1]
 | ||
|  | ; CHECK-NOT: alloca
 | ||
|  | 	%cast = getelementptr [10 x i8], [10 x i8]* %storage, i32 0, i32 0		; <i8*> [#uses=1]
 | ||
|  | 	call void @llvm.init.trampoline( i8* %cast, i8* bitcast (void ()* @test11f to i8*), i8* null )		; <i8*> [#uses=1]
 | ||
|  | ; CHECK-NOT: trampoline
 | ||
|  | 	ret void | ||
|  | ; CHECK: ret void
 | ||
|  | } | ||
|  | 
 | ||
|  | 
 | ||
|  | ; PR2599 - load -> store to same address.
 | ||
|  | define void @test12({ i32, i32 }* %x) nounwind  { | ||
|  | 	%tmp4 = getelementptr { i32, i32 }, { i32, i32 }* %x, i32 0, i32 0 | ||
|  | 	%tmp5 = load i32, i32* %tmp4, align 4 | ||
|  | 	%tmp7 = getelementptr { i32, i32 }, { i32, i32 }* %x, i32 0, i32 1 | ||
|  | 	%tmp8 = load i32, i32* %tmp7, align 4 | ||
|  | 	%tmp17 = sub i32 0, %tmp8 | ||
|  | 	store i32 %tmp5, i32* %tmp4, align 4 | ||
|  | 	store i32 %tmp17, i32* %tmp7, align 4 | ||
|  | 	ret void | ||
|  | ; CHECK-LABEL: @test12(
 | ||
|  | ; CHECK-NOT: tmp5
 | ||
|  | ; CHECK: ret void
 | ||
|  | } | ||
|  | 
 | ||
|  | 
 | ||
|  | ; %P doesn't escape, the DEAD instructions should be removed.
 | ||
|  | declare void @test13f() | ||
|  | define i32* @test13() { | ||
|  |         %p = tail call i8* @malloc(i32 4) | ||
|  |         %P = bitcast i8* %p to i32* | ||
|  |         %DEAD = load i32, i32* %P | ||
|  |         %DEAD2 = add i32 %DEAD, 1 | ||
|  |         store i32 %DEAD2, i32* %P | ||
|  |         call void @test13f( ) | ||
|  |         store i32 0, i32* %P | ||
|  |         ret i32* %P | ||
|  | ; CHECK: @test13()
 | ||
|  | ; CHECK-NEXT: malloc
 | ||
|  | ; CHECK-NEXT: bitcast
 | ||
|  | ; CHECK-NEXT: call void
 | ||
|  | } | ||
|  | 
 | ||
|  | define i32 addrspace(1)* @test13_addrspacecast() { | ||
|  |   %p = tail call i8* @malloc(i32 4) | ||
|  |   %p.bc = bitcast i8* %p to i32* | ||
|  |   %P = addrspacecast i32* %p.bc to i32 addrspace(1)* | ||
|  |   %DEAD = load i32, i32 addrspace(1)* %P | ||
|  |   %DEAD2 = add i32 %DEAD, 1 | ||
|  |   store i32 %DEAD2, i32 addrspace(1)* %P | ||
|  |   call void @test13f( ) | ||
|  |   store i32 0, i32 addrspace(1)* %P | ||
|  |   ret i32 addrspace(1)* %P | ||
|  | ; CHECK: @test13_addrspacecast()
 | ||
|  | ; CHECK-NEXT: malloc
 | ||
|  | ; CHECK-NEXT: bitcast
 | ||
|  | ; CHECK-NEXT: addrspacecast
 | ||
|  | ; CHECK-NEXT: call void
 | ||
|  | } | ||
|  | 
 | ||
|  | declare noalias i8* @malloc(i32) | ||
|  | declare noalias i8* @calloc(i32, i32) | ||
|  | 
 | ||
|  | 
 | ||
|  | define void @test14(i32* %Q) { | ||
|  |         %P = alloca i32 | ||
|  |         %DEAD = load i32, i32* %Q | ||
|  |         store i32 %DEAD, i32* %P | ||
|  |         ret void | ||
|  | 
 | ||
|  | ; CHECK-LABEL: @test14(
 | ||
|  | ; CHECK-NEXT: ret void
 | ||
|  | } | ||
|  | 
 | ||
|  | 
 | ||
|  | ; PR8701
 | ||
|  | 
 | ||
|  | ;; Fully dead overwrite of memcpy.
 | ||
|  | define void @test15(i8* %P, i8* %Q) nounwind ssp { | ||
|  |   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false) | ||
|  |   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false) | ||
|  |   ret void | ||
|  | ; CHECK-LABEL: @test15(
 | ||
|  | ; CHECK-NEXT: call void @llvm.memcpy
 | ||
|  | ; CHECK-NEXT: ret
 | ||
|  | } | ||
|  | 
 | ||
|  | ;; Full overwrite of smaller memcpy.
 | ||
|  | define void @test16(i8* %P, i8* %Q) nounwind ssp { | ||
|  |   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 8, i32 1, i1 false) | ||
|  |   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false) | ||
|  |   ret void | ||
|  | ; CHECK-LABEL: @test16(
 | ||
|  | ; CHECK-NEXT: call void @llvm.memcpy
 | ||
|  | ; CHECK-NEXT: ret
 | ||
|  | } | ||
|  | 
 | ||
|  | ;; Overwrite of memset by memcpy.
 | ||
|  | define void @test17(i8* %P, i8* noalias %Q) nounwind ssp { | ||
|  |   tail call void @llvm.memset.p0i8.i64(i8* %P, i8 42, i64 8, i32 1, i1 false) | ||
|  |   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false) | ||
|  |   ret void | ||
|  | ; CHECK-LABEL: @test17(
 | ||
|  | ; CHECK-NEXT: call void @llvm.memcpy
 | ||
|  | ; CHECK-NEXT: ret
 | ||
|  | } | ||
|  | 
 | ||
|  | ; Should not delete the volatile memset.
 | ||
|  | define void @test17v(i8* %P, i8* %Q) nounwind ssp { | ||
|  |   tail call void @llvm.memset.p0i8.i64(i8* %P, i8 42, i64 8, i32 1, i1 true) | ||
|  |   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false) | ||
|  |   ret void | ||
|  | ; CHECK-LABEL: @test17v(
 | ||
|  | ; CHECK-NEXT: call void @llvm.memset
 | ||
|  | ; CHECK-NEXT: call void @llvm.memcpy
 | ||
|  | ; CHECK-NEXT: ret
 | ||
|  | } | ||
|  | 
 | ||
|  | ; PR8728
 | ||
|  | ; Do not delete instruction where possible situation is:
 | ||
|  | ; A = B
 | ||
|  | ; A = A
 | ||
|  | define void @test18(i8* %P, i8* %Q, i8* %R) nounwind ssp { | ||
|  |   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i32 1, i1 false) | ||
|  |   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %R, i64 12, i32 1, i1 false) | ||
|  |   ret void | ||
|  | ; CHECK-LABEL: @test18(
 | ||
|  | ; CHECK-NEXT: call void @llvm.memcpy
 | ||
|  | ; CHECK-NEXT: call void @llvm.memcpy
 | ||
|  | ; CHECK-NEXT: ret
 | ||
|  | } | ||
|  | 
 | ||
|  | 
 | ||
|  | ; The store here is not dead because the byval call reads it.
 | ||
|  | declare void @test19f({i32}* byval align 4 %P) | ||
|  | 
 | ||
|  | define void @test19({i32} * nocapture byval align 4 %arg5) nounwind ssp { | ||
|  | bb: | ||
|  |   %tmp7 = getelementptr inbounds {i32}, {i32}* %arg5, i32 0, i32 0 | ||
|  |   store i32 912, i32* %tmp7 | ||
|  |   call void @test19f({i32}* byval align 4 %arg5) | ||
|  |   ret void | ||
|  | 
 | ||
|  | ; CHECK-LABEL: @test19(
 | ||
|  | ; CHECK: store i32 912
 | ||
|  | ; CHECK: call void @test19f
 | ||
|  | } | ||
|  | 
 | ||
|  | define void @test20() { | ||
|  |   %m = call i8* @malloc(i32 24) | ||
|  |   store i8 0, i8* %m | ||
|  |   ret void | ||
|  | } | ||
|  | ; CHECK-LABEL: @test20(
 | ||
|  | ; CHECK-NEXT: ret void
 | ||
|  | 
 | ||
|  | ; CHECK-LABEL: @test21(
 | ||
|  | define void @test21() { | ||
|  |   %m = call i8* @calloc(i32 9, i32 7) | ||
|  |   store i8 0, i8* %m | ||
|  | ; CHECK-NEXT: ret void
 | ||
|  |   ret void | ||
|  | } | ||
|  | 
 | ||
|  | ; CHECK-LABEL: @test22(
 | ||
|  | define void @test22(i1 %i, i32 %k, i32 %m) nounwind { | ||
|  |   %k.addr = alloca i32 | ||
|  |   %m.addr = alloca i32 | ||
|  |   %k.addr.m.addr = select i1 %i, i32* %k.addr, i32* %m.addr | ||
|  |   store i32 0, i32* %k.addr.m.addr, align 4 | ||
|  | ; CHECK-NEXT: ret void
 | ||
|  |   ret void | ||
|  | } | ||
|  | 
 | ||
|  | ; PR13547
 | ||
|  | ; CHECK-LABEL: @test23(
 | ||
|  | ; CHECK: store i8 97
 | ||
|  | ; CHECK: store i8 0
 | ||
|  | declare noalias i8* @strdup(i8* nocapture) nounwind | ||
|  | define noalias i8* @test23() nounwind uwtable ssp { | ||
|  |   %x = alloca [2 x i8], align 1 | ||
|  |   %arrayidx = getelementptr inbounds [2 x i8], [2 x i8]* %x, i64 0, i64 0 | ||
|  |   store i8 97, i8* %arrayidx, align 1 | ||
|  |   %arrayidx1 = getelementptr inbounds [2 x i8], [2 x i8]* %x, i64 0, i64 1 | ||
|  |   store i8 0, i8* %arrayidx1, align 1 | ||
|  |   %call = call i8* @strdup(i8* %arrayidx) nounwind | ||
|  |   ret i8* %call | ||
|  | } | ||
|  | 
 | ||
|  | ; Make sure same sized store to later element is deleted
 | ||
|  | ; CHECK-LABEL: @test24(
 | ||
|  | ; CHECK-NOT: store i32 0
 | ||
|  | ; CHECK-NOT: store i32 0
 | ||
|  | ; CHECK: store i32 %b
 | ||
|  | ; CHECK: store i32 %c
 | ||
|  | ; CHECK: ret void
 | ||
|  | define void @test24([2 x i32]* %a, i32 %b, i32 %c) nounwind { | ||
|  |   %1 = getelementptr inbounds [2 x i32], [2 x i32]* %a, i64 0, i64 0 | ||
|  |   store i32 0, i32* %1, align 4 | ||
|  |   %2 = getelementptr inbounds [2 x i32], [2 x i32]* %a, i64 0, i64 1 | ||
|  |   store i32 0, i32* %2, align 4 | ||
|  |   %3 = getelementptr inbounds [2 x i32], [2 x i32]* %a, i64 0, i64 0 | ||
|  |   store i32 %b, i32* %3, align 4 | ||
|  |   %4 = getelementptr inbounds [2 x i32], [2 x i32]* %a, i64 0, i64 1 | ||
|  |   store i32 %c, i32* %4, align 4 | ||
|  |   ret void | ||
|  | } | ||
|  | 
 | ||
|  | ; Check another case like PR13547 where strdup is not like malloc.
 | ||
|  | ; CHECK-LABEL: @test25(
 | ||
|  | ; CHECK: load i8
 | ||
|  | ; CHECK: store i8 0
 | ||
|  | ; CHECK: store i8 %tmp
 | ||
|  | define i8* @test25(i8* %p) nounwind { | ||
|  |   %p.4 = getelementptr i8, i8* %p, i64 4 | ||
|  |   %tmp = load i8, i8* %p.4, align 1 | ||
|  |   store i8 0, i8* %p.4, align 1 | ||
|  |   %q = call i8* @strdup(i8* %p) nounwind optsize | ||
|  |   store i8 %tmp, i8* %p.4, align 1 | ||
|  |   ret i8* %q | ||
|  | } | ||
|  | 
 | ||
|  | ; Remove redundant store if loaded value is in another block.
 | ||
|  | ; CHECK-LABEL: @test26(
 | ||
|  | ; CHECK-NOT: store
 | ||
|  | ; CHECK: ret
 | ||
|  | define i32 @test26(i1 %c, i32* %p) { | ||
|  | entry: | ||
|  |   %v = load i32, i32* %p, align 4 | ||
|  |   br i1 %c, label %bb1, label %bb2 | ||
|  | bb1: | ||
|  |   br label %bb3 | ||
|  | bb2: | ||
|  |   store i32 %v, i32* %p, align 4 | ||
|  |   br label %bb3 | ||
|  | bb3: | ||
|  |   ret i32 0 | ||
|  | } | ||
|  | 
 | ||
|  | ; Remove redundant store if loaded value is in another block.
 | ||
|  | ; CHECK-LABEL: @test27(
 | ||
|  | ; CHECK-NOT: store
 | ||
|  | ; CHECK: ret
 | ||
|  | define i32 @test27(i1 %c, i32* %p) { | ||
|  | entry: | ||
|  |   %v = load i32, i32* %p, align 4 | ||
|  |   br i1 %c, label %bb1, label %bb2 | ||
|  | bb1: | ||
|  |   br label %bb3 | ||
|  | bb2: | ||
|  |   br label %bb3 | ||
|  | bb3: | ||
|  |   store i32 %v, i32* %p, align 4 | ||
|  |   ret i32 0 | ||
|  | } | ||
|  | 
 | ||
|  | ; Don't remove redundant store because of may-aliased store.
 | ||
|  | ; CHECK-LABEL: @test28(
 | ||
|  | ; CHECK: bb3:
 | ||
|  | ; CHECK-NEXT: store i32 %v
 | ||
|  | define i32 @test28(i1 %c, i32* %p, i32* %p2, i32 %i) { | ||
|  | entry: | ||
|  |   %v = load i32, i32* %p, align 4 | ||
|  | 
 | ||
|  |   ; Might overwrite value at %p
 | ||
|  |   store i32 %i, i32* %p2, align 4 | ||
|  |   br i1 %c, label %bb1, label %bb2 | ||
|  | bb1: | ||
|  |   br label %bb3 | ||
|  | bb2: | ||
|  |   br label %bb3 | ||
|  | bb3: | ||
|  |   store i32 %v, i32* %p, align 4 | ||
|  |   ret i32 0 | ||
|  | } | ||
|  | 
 | ||
|  | ; Don't remove redundant store because of may-aliased store.
 | ||
|  | ; CHECK-LABEL: @test29(
 | ||
|  | ; CHECK: bb3:
 | ||
|  | ; CHECK-NEXT: store i32 %v
 | ||
|  | define i32 @test29(i1 %c, i32* %p, i32* %p2, i32 %i) { | ||
|  | entry: | ||
|  |   %v = load i32, i32* %p, align 4 | ||
|  |   br i1 %c, label %bb1, label %bb2 | ||
|  | bb1: | ||
|  |   br label %bb3 | ||
|  | bb2: | ||
|  |   ; Might overwrite value at %p
 | ||
|  |   store i32 %i, i32* %p2, align 4 | ||
|  |   br label %bb3 | ||
|  | bb3: | ||
|  |   store i32 %v, i32* %p, align 4 | ||
|  |   ret i32 0 | ||
|  | } | ||
|  | 
 | ||
|  | declare void @unknown_func() | ||
|  | 
 | ||
|  | ; Don't remove redundant store because of unknown call.
 | ||
|  | ; CHECK-LABEL: @test30(
 | ||
|  | ; CHECK: bb3:
 | ||
|  | ; CHECK-NEXT: store i32 %v
 | ||
|  | define i32 @test30(i1 %c, i32* %p, i32 %i) { | ||
|  | entry: | ||
|  |   %v = load i32, i32* %p, align 4 | ||
|  |   br i1 %c, label %bb1, label %bb2 | ||
|  | bb1: | ||
|  |   br label %bb3 | ||
|  | bb2: | ||
|  |   ; Might overwrite value at %p
 | ||
|  |   call void @unknown_func() | ||
|  |   br label %bb3 | ||
|  | bb3: | ||
|  |   store i32 %v, i32* %p, align 4 | ||
|  |   ret i32 0 | ||
|  | } | ||
|  | 
 | ||
|  | ; Remove redundant store if loaded value is in another block inside a loop.
 | ||
|  | ; CHECK-LABEL: @test31(
 | ||
|  | ; CHECK-NOT: store
 | ||
|  | ; CHECK: ret
 | ||
|  | define i32 @test31(i1 %c, i32* %p, i32 %i) { | ||
|  | entry: | ||
|  |   %v = load i32, i32* %p, align 4 | ||
|  |   br label %bb1 | ||
|  | bb1: | ||
|  |   store i32 %v, i32* %p, align 4 | ||
|  |   br i1 undef, label %bb1, label %bb2 | ||
|  | bb2: | ||
|  |   ret i32 0 | ||
|  | } | ||
|  | 
 | ||
|  | ; Don't remove redundant store in a loop with a may-alias store.
 | ||
|  | ; CHECK-LABEL: @test32(
 | ||
|  | ; CHECK: bb1:
 | ||
|  | ; CHECK-NEXT: store i32 %v
 | ||
|  | ; CHECK-NEXT: call void @unknown_func
 | ||
|  | define i32 @test32(i1 %c, i32* %p, i32 %i) { | ||
|  | entry: | ||
|  |   %v = load i32, i32* %p, align 4 | ||
|  |   br label %bb1 | ||
|  | bb1: | ||
|  |   store i32 %v, i32* %p, align 4 | ||
|  |   ; Might read and overwrite value at %p
 | ||
|  |   call void @unknown_func() | ||
|  |   br i1 undef, label %bb1, label %bb2 | ||
|  | bb2: | ||
|  |   ret i32 0 | ||
|  | } | ||
|  | 
 | ||
|  | ; Remove redundant store, which is in the lame loop as the load.
 | ||
|  | ; CHECK-LABEL: @test33(
 | ||
|  | ; CHECK-NOT: store
 | ||
|  | ; CHECK: ret
 | ||
|  | define i32 @test33(i1 %c, i32* %p, i32 %i) { | ||
|  | entry: | ||
|  |   br label %bb1 | ||
|  | bb1: | ||
|  |   %v = load i32, i32* %p, align 4 | ||
|  |   br label %bb2 | ||
|  | bb2: | ||
|  |   store i32 %v, i32* %p, align 4 | ||
|  |   ; Might read and overwrite value at %p, but doesn't matter.
 | ||
|  |   call void @unknown_func() | ||
|  |   br i1 undef, label %bb1, label %bb3 | ||
|  | bb3: | ||
|  |   ret i32 0 | ||
|  | } | ||
|  | 
 | ||
|  | ; Don't remove redundant store: unknown_func could unwind
 | ||
|  | ; CHECK-LABEL: @test34(
 | ||
|  | ; CHECK: store i32 1
 | ||
|  | ; CHECK: store i32 0
 | ||
|  | ; CHECK: ret
 | ||
|  | define void @test34(i32* noalias %p) { | ||
|  |   store i32 1, i32* %p | ||
|  |   call void @unknown_func() | ||
|  |   store i32 0, i32* %p | ||
|  |   ret void | ||
|  | } | ||
|  | 
 | ||
|  | ; Remove redundant store even with an unwinding function in the same block
 | ||
|  | ; CHECK-LABEL: @test35(
 | ||
|  | ; CHECK: call void @unknown_func
 | ||
|  | ; CHECK-NEXT: store i32 0
 | ||
|  | ; CHECK-NEXT: ret void
 | ||
|  | define void @test35(i32* noalias %p) { | ||
|  |   call void @unknown_func() | ||
|  |   store i32 1, i32* %p | ||
|  |   store i32 0, i32* %p | ||
|  |   ret void | ||
|  | } |