Add DIExpression::foldConstantMath to CoroSplit (llvm#107933)

The CoroSplit pass has it's own salvageDebugInfo implementation and it's DIExpressions do not get folded. Add a call to DIExpression::foldConstantMath in the CoroSplit pass to reduce the size of those DIExpressions. [The compile time tracker shows no significant increase in compile time either.](https://llvm-compile-time-tracker.com/compare.php?from=bdf02249e7f8f95177ff58c881caf219699acb98&to=e1c1c1759c06bc4c42f79eebdb0e3cd45219cef4&stat=instructions:u) rdar://134675402
zhaoshiz · Sep 10, 2024 · 7a91af4 · 7a91af4
1 parent 02c943a
commit 7a91af4
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Showing 2 changed files with 5 additions and 4 deletions.
diff --git a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
@@ -2659,6 +2659,7 @@ salvageDebugInfoImpl(SmallDenseMap<Argument *, AllocaInst *, 4> &ArgToAllocaMap,
     Expr = DIExpression::prepend(Expr, DIExpression::DerefBefore);
   }
 
+  Expr = Expr->foldConstantMath();
   return {{*Storage, *Expr}};
 }
 

diff --git a/llvm/test/Transforms/Coroutines/swift-async-dbg.ll b/llvm/test/Transforms/Coroutines/swift-async-dbg.ll
@@ -30,7 +30,7 @@ define swifttailcc void @coroutineA(ptr swiftasync %arg) !dbg !48 {
 ; CHECK-LABEL: define {{.*}} @coroutineA(
 ; CHECK-SAME:    ptr swiftasync %[[frame_ptr:.*]])
 ; CHECK:      #dbg_declare(ptr %[[frame_ptr]], {{.*}} !DIExpression(
-; CHECK-SAME:                   DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 8)
+; CHECK-SAME:                   DW_OP_plus_uconst, 24)
 ; CHECK:      #dbg_value(ptr %[[frame_ptr]], {{.*}} !DIExpression(
 ; CHECK-SAME:                 DW_OP_plus_uconst, 16, DW_OP_deref)
 ; CHECK:      call {{.*}} @swift_task_switch
@@ -49,7 +49,7 @@ define swifttailcc void @coroutineA(ptr swiftasync %arg) !dbg !48 {
 ; CHECK-LABEL: define {{.*}} @coroutineATY0_(
 ; CHECK-SAME:    ptr swiftasync %[[frame_ptr:.*]])
 ; CHECK:      #dbg_declare(ptr %[[frame_ptr]], {{.*}} !DIExpression(
-; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 8)
+; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 24)
 ; CHECK:      #dbg_value(ptr %[[frame_ptr]], {{.*}} !DIExpression(
 ; CHECK-SAME:                 DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 16, DW_OP_deref)
 ; CHECK:      #dbg_value(!DIArgList(ptr %[[frame_ptr]], i32 %{{.*}}), {{.*}} !DIExpression(
@@ -70,7 +70,7 @@ define swifttailcc void @coroutineA(ptr swiftasync %arg) !dbg !48 {
 ; CHECK-SAME:    ptr swiftasync %[[frame_ptr:.*]])
 ; Note the extra level of indirection that shows up here!
 ; CHECK:      #dbg_declare(ptr %[[frame_ptr]], {{.*}} !DIExpression(
-; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_deref, DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 8)
+; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_deref, DW_OP_plus_uconst, 24)
 ; CHECK:      #dbg_value(ptr %[[frame_ptr]], {{.*}} !DIExpression(
 ; CHECK-SAME:                 DW_OP_LLVM_entry_value, 1, DW_OP_deref, DW_OP_plus_uconst, 16, DW_OP_deref)
 ; CHECK:      call {{.*}} @swift_task_switch
@@ -85,7 +85,7 @@ define swifttailcc void @coroutineA(ptr swiftasync %arg) !dbg !48 {
 ; CHECK-LABEL: define {{.*}} @coroutineATY2_(
 ; CHECK-SAME:    ptr swiftasync %[[frame_ptr:.*]])
 ; CHECK:      #dbg_declare(ptr %[[frame_ptr]], {{.*}} !DIExpression(
-; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 16, DW_OP_plus_uconst, 8)
+; CHECK-SAME:                   DW_OP_LLVM_entry_value, 1, DW_OP_plus_uconst, 24)
 }
 
 ; Everything from here on is just support code for the coroutines.
-Original file line number
+Diff line change
@@ Expand Up @@
         Expr = DIExpression::prepend(Expr, DIExpression::DerefBefore);
       }
+      Expr = Expr->foldConstantMath();
       return {{*Storage, *Expr}};
     }
@@ Expand Down @@