Remove StructRet arg attr

It is applied exactly when the return value has an indirect pass mode.
Except for InReg on x86 fastcall, arg attrs are now only used for
optimization purposes and thus are fine to ignore.

3 files changed, 6 insertions, 12 deletions

diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs
index e988fdb9d5c..bb152104d64 100644
--- a/compiler/rustc_codegen_llvm/src/abi.rs
+++ b/compiler/rustc_codegen_llvm/src/abi.rs
@@ -36,7 +36,7 @@ impl ArgAttributeExt for ArgAttribute {
     where
         F: FnMut(llvm::Attribute),
     {
-        for_each_kind!(self, f, NoAlias, NoCapture, NonNull, ReadOnly, StructRet, InReg)
+        for_each_kind!(self, f, NoAlias, NoCapture, NonNull, ReadOnly, InReg)
     }
 }
 
@@ -429,7 +429,8 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             }
             PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => {
                 assert!(!on_stack);
-                apply(attrs);
+                let i = apply(attrs);
+                llvm::Attribute::StructRet.apply_llfn(llvm::AttributePlace::Argument(i), llfn);
             }
             _ => {}
         }
@@ -484,7 +485,9 @@ impl<'tcx> FnAbiLlvmExt<'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             }
             PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => {
                 assert!(!on_stack);
-                apply(attrs);
+                let i = apply(attrs);
+                llvm::Attribute::StructRet
+                    .apply_callsite(llvm::AttributePlace::Argument(i), callsite);
             }
             _ => {}
         }
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index 24d2ee6ec34..666160ba497 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -2801,10 +2801,6 @@ where
             for arg in &mut self.args {
                 fixup(arg, false);
             }
-            if let PassMode::Indirect { ref mut attrs, extra_attrs: _, on_stack: _ } = self.ret.mode
-            {
-                attrs.set(ArgAttribute::StructRet);
-            }
             return;
         }
 
diff --git a/compiler/rustc_target/src/abi/call/mod.rs b/compiler/rustc_target/src/abi/call/mod.rs
index 0931e8a3771..91b004c41d9 100644
--- a/compiler/rustc_target/src/abi/call/mod.rs
+++ b/compiler/rustc_target/src/abi/call/mod.rs
@@ -59,7 +59,6 @@ mod attr_impl {
             const NoCapture = 1 << 2;
             const NonNull   = 1 << 3;
             const ReadOnly  = 1 << 4;
-            const StructRet = 1 << 6;
             const InReg     = 1 << 8;
         }
     }
@@ -619,10 +618,6 @@ impl<'a, Ty> FnAbi<'a, Ty> {
             a => return Err(format!("unrecognized arch \"{}\" in target specification", a)),
         }
 
-        if let PassMode::Indirect { ref mut attrs, extra_attrs: _, on_stack: _ } = self.ret.mode {
-            attrs.set(ArgAttribute::StructRet);
-        }
-
         Ok(())
     }
 }