Improve GVN storage tests

Author: ohadravid

tests/mir-opt/gvn_storage_issue_141649.f.GVN.diff

@@ -0,0 +1,20 @@
+- // MIR for `f` before GVN
++ // MIR for `f` after GVN
+  
+  fn f(_1: u32) -> () {
+      let mut _0: ();
+      let mut _2: S;
+      let mut _3: S;
+  
+      bb0: {
+          StorageLive(_2);
+          _2 = S(copy _1, const 2_u32);
+          StorageLive(_3);
+-         _3 = S(copy _1, const 2_u32);
++         _3 = copy _2;
+          StorageDead(_3);
+          StorageDead(_2);
+          return;
+      }
+  }
+  

tests/mir-opt/gvn_storage_issue_141649.rs

@@ -0,0 +1,32 @@
+//! Check that we do not remove storage statements when possible.
+//@ test-mir-pass: GVN
+// EMIT_MIR gvn_storage_issue_141649.f.GVN.diff
+
+#![feature(custom_mir, core_intrinsics)]
+
+use std::intrinsics::mir::*;
+
+struct S(u32, u32);
+
+#[custom_mir(dialect = "runtime")]
+pub fn f(_1: u32) {
+    // CHECK-LABEL: fn f(
+    mir! {
+        let _2: S;
+        let _3: S;
+        {
+            // CHECK: StorageLive(_2);
+            // CHECK: StorageLive(_3);
+            // CHECK: _3 = copy _2;
+            // CHECK: StorageDead(_3);
+            // CHECK: StorageDead(_2);
+            StorageLive(_2);
+            _2 = S(_1, 2);
+            StorageLive(_3);
+            _3 = S(_1, 2);
+            StorageDead(_3);
+            StorageDead(_2);
+            Return()
+        }
+    }
+}

tests/mir-opt/gvn_storage_issue_141649_debug.f.GVN.diff

@@ -0,0 +1,22 @@
+- // MIR for `f` before GVN
++ // MIR for `f` after GVN
+  
+  fn f(_1: u32) -> () {
+      let mut _0: ();
+      let mut _2: S;
+      let mut _3: S;
+  
+      bb0: {
+-         StorageLive(_2);
++         nop;
+          _2 = S(copy _1, const 2_u32);
+          StorageLive(_3);
+-         _3 = S(copy _1, const 2_u32);
++         _3 = copy _2;
+          StorageDead(_3);
+-         StorageDead(_2);
++         nop;
+          return;
+      }
+  }
+  

tests/mir-opt/gvn_storage_issue_141649_debug.rs

@@ -0,0 +1,31 @@
+//! In lower opt levels, we remove any storage statements of reused locals.
+//@ test-mir-pass: GVN
+//@ compile-flags: -Copt-level=0
+// EMIT_MIR gvn_storage_issue_141649_debug.f.GVN.diff
+
+#![feature(custom_mir, core_intrinsics)]
+
+use std::intrinsics::mir::*;
+
+struct S(u32, u32);
+
+#[custom_mir(dialect = "runtime")]
+pub fn f(_1: u32) {
+    // CHECK-LABEL: fn f(
+    mir! {
+        let _2: S;
+        let _3: S;
+        {
+            // CHECK-NOT: StorageLive(_2);
+            // CHECK: _3 = copy _2;
+            // CHECK-NOT: StorageDead(_2);
+            StorageLive(_2);
+            _2 = S(_1, 2);
+            StorageLive(_3);
+            _3 = S(_1, 2);
+            StorageDead(_3);
+            StorageDead(_2);
+            Return()
+        }
+    }
+}

tests/mir-opt/gvn_storage_twice.rs

@@ -1,4 +1,3 @@
-// skip-filecheck
 //@ test-mir-pass: GVN
 //@ compile-flags: -Zlint-mir=false
 
@@ -18,10 +17,12 @@ use std::intrinsics::mir::*;
 
 #[custom_mir(dialect = "runtime")]
 pub fn repeat_local(_1: usize, _2: usize, _3: i32) -> i32 {
+    // CHECK-LABEL: fn repeat_local(
     mir! {
         {
             let _4 = [_3; 5];
             let _5 = &_4[_1];
+            // CHECK: _0 = copy _3;
             RET = *_5;
             Return()
         }
@@ -32,11 +33,13 @@ pub fn repeat_local(_1: usize, _2: usize, _3: i32) -> i32 {
 
 #[custom_mir(dialect = "runtime")]
 pub fn repeat_local_dead(_1: usize, _2: usize, _3: i32) -> i32 {
+    // CHECK-LABEL: fn repeat_local_dead(
     mir! {
         {
             let _4 = [_3; 5];
             let _5 = &_4[_1];
             StorageDead(_3);
+            // CHECK: _0 = copy _3;
             RET = *_5;
             Return()
         }
@@ -47,12 +50,14 @@ pub fn repeat_local_dead(_1: usize, _2: usize, _3: i32) -> i32 {
 
 #[custom_mir(dialect = "runtime")]
 pub fn repeat_local_dead_live(_1: usize, _2: usize, _3: i32) -> i32 {
+    // CHECK-LABEL: fn repeat_local_dead_live(
     mir! {
         {
             let _4 = [_3; 5];
             let _5 = &_4[_1];
             StorageDead(_3);
             StorageLive(_3);
+            // CHECK: _0 = copy _3;
             RET = *_5;
             Return()
         }