[PATCH] D90258: [InstCombine] Do not introduce bitcasts for swifterror arguments.

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
fhahn added reviewers: spatel, lebedev.ri, rjmccall, xbolva00.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.
fhahn requested review of this revision.

The following constraints hold for swifterror values:

  A swifterror value (either the parameter or the alloca) can only
  be loaded and stored from, or used as a swifterror argument.

This patch updates instcombine to not try to convert a bitcast of a
function into a bitcast of a swifterror argument.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D90258

Files:
  llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
  llvm/test/Transforms/InstCombine/swifterror-argument-bitcast-fold.ll


Index: llvm/test/Transforms/InstCombine/swifterror-argument-bitcast-fold.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/InstCombine/swifterror-argument-bitcast-fold.ll
@@ -0,0 +1,13 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; opt -instcombine -S %s | FileCheck %s
+
+; The swifterror value can only be loaded, stored or used as swifterror
+; argument. Make sure we do not try to turn the function bitcast into an
+; argument bitcast.
+define swiftcc void @spam(i32** swifterror %arg) {
+bb:
+  call swiftcc void bitcast (void (i64**)* @widget to void (i32**)*)(i32** swifterror %arg)
+  ret void
+}
+
+declare swiftcc void @widget(i64**)
Index: llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2126,6 +2126,9 @@
     if (Call.isInAllocaArgument(i))
       return false;   // Cannot transform to and from inalloca.
 
+    if (CallerPAL.hasParamAttribute(i, Attribute::SwiftError))
+      return false;
+
     // If the parameter is passed as a byval argument, then we have to have a
     // sized type and the sized type has to have the same size as the old type.
     if (ParamTy != ActTy && CallerPAL.hasParamAttribute(i, Attribute::ByVal)) {


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D90258.301075.patch
Type: text/x-patch
Size: 1434 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20201027/56c7b239/attachment.bin>