| ; RUN: opt -S -passes=dse < %s | FileCheck %s |
| |
| declare void @f() |
| declare noalias ptr @malloc(i32) nounwind |
| |
| define void @test_0() { |
| ; CHECK-LABEL: @test_0( |
| %m = call ptr @malloc(i32 24) |
| tail call void @f() [ "unknown"(ptr %m) ] |
| ; CHECK: store i8 -19, ptr %m |
| store i8 -19, ptr %m |
| ret void |
| } |
| |
| define ptr @test_1() { |
| ; CHECK-LABEL: @test_1( |
| %m = call ptr @malloc(i32 24) |
| tail call void @f() [ "unknown"(ptr %m) ] |
| store i8 -19, ptr %m |
| tail call void @f() |
| store i8 101, ptr %m |
| |
| ; CHECK: tail call void @f() [ "unknown"(ptr %m) ] |
| ; CHECK: store i8 -19, ptr %m |
| ; CHECK: tail call void @f() |
| ; CHECK: store i8 101, ptr %m |
| |
| ret ptr %m |
| } |
| |
| define void @test_2() { |
| ; Since the deopt operand bundle does not escape %m (see caveat below), it is |
| ; legal to elide the final store that location. |
| |
| ; CHECK-LABEL: @test_2( |
| %m = call ptr @malloc(i32 24) |
| tail call void @f() [ "deopt"(ptr %m) ] |
| store i8 -19, ptr %m |
| ret void |
| |
| ; CHECK: tail call void @f() [ "deopt"(ptr %m) ] |
| ; CHECK-NEXT: ret void |
| } |
| |
| define ptr @test_3() { |
| ; Since the deopt operand bundle does not escape %m (see caveat below), @f |
| ; cannot observe the stores to %m |
| |
| ; CHECK-LABEL: @test_3( |
| %m = call ptr @malloc(i32 24) |
| tail call void @f() [ "deopt"(ptr %m) ] |
| store i8 -19, ptr %m |
| tail call void @f() |
| store i8 101, ptr %m |
| ret ptr %m |
| } |
| |
| |
| ; Caveat: technically, %m can only escape if the calling function is deoptimized |
| ; at the call site (i.e. the call returns to the "deopt" continuation). Since |
| ; the calling function body will be invalidated in that case, the calling |
| ; function can be optimized under the assumption that %m does not escape. |