[llvm-commits] [llvm] r140902 - in /llvm/trunk: lib/CodeGen/SelectionDAG/SelectionDAG.cpp test/CodeGen/X86/alignment-2.ll

[Bill Wendling]

Author: void
Date: Fri Sep 30 18:19:55 2011
New Revision: 140902

URL: http://llvm.org/viewvc/llvm-project?rev=140902&view=rev
Log:
When inferring the pointer alignment, if the global doesn't have an initializer
and the alignment is 0 (i.e., it's defined globally in one file and declared in
another file) it could get an alignment which is larger than the ABI allows for
that type, resulting in aligned moves being used for unaligned loads.

For instance, in file A.c:

   struct S s;

In file B.c:
   struct {
     // something long
   };
   extern S s;

   void foo() {
     struct S p = s;
     // ...
   }

this copy is a 'memcpy' which is turned into a series of 'movaps' instructions
on X86. But this is wrong, because 'struct S' has alignment of 4, not 16.

Added:
    llvm/trunk/test/CodeGen/X86/alignment-2.ll
Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=140902&r1=140901&r2=140902&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Fri Sep 30 18:19:55 2011
@@ -6537,6 +6537,8 @@
           Align = TD->getPreferredAlignment(GVar);
         }
       }
+      if (!Align)
+        Align = TLI.getTargetData()->getABITypeAlignment(GV->getType());
     }
     return MinAlign(Align, GVOffset);
   }

Added: llvm/trunk/test/CodeGen/X86/alignment-2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/alignment-2.ll?rev=140902&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/alignment-2.ll (added)
+++ llvm/trunk/test/CodeGen/X86/alignment-2.ll Fri Sep 30 18:19:55 2011
@@ -0,0 +1,26 @@
+; RUN: llc < %s -mtriple i386-apple-darwin10 | not grep movaps
+; <rdar://problem/10058036>
+
+%struct._psqlSettings = type { %struct.pg_conn*, i32, %struct.__sFILE*, i8, %struct.printQueryOpt, i8*, i8, i32, %struct.__sFILE*, i8, i32, i8*, i8*, i8*, i64, i8, %struct.__sFILE*, %struct._variable*, i8, i8, i8, i8, i8, i32, i32, i32, i32, i32, i8*, i8*, i8*, i32 }
+%struct.pg_conn = type opaque
+%struct.__sFILE = type { i8*, i32, i32, i16, i16, %struct.__sbuf, i32, i8*, i32 (i8*)*, i32 (i8*, i8*, i32)*, i64 (i8*, i64, i32)*, i32 (i8*, i8*, i32)*, %struct.__sbuf, %struct.__sFILEX*, i32, [3 x i8], [1 x i8], %struct.__sbuf, i32, i64 }
+%struct.__sbuf = type { i8*, i32 }
+%struct.__sFILEX = type opaque
+%struct.printQueryOpt = type { %struct.printTableOpt, i8*, i8, i8*, i8**, i8, i8, i8* }
+%struct.printTableOpt = type { i32, i8, i16, i16, i8, i8, i8, i32, %struct.printTextFormat*, i8*, i8*, i8, i8*, i32, i32, i32 }
+%struct.printTextFormat = type { i8*, [4 x %struct.printTextLineFormat], i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8 }
+%struct.printTextLineFormat = type { i8*, i8*, i8*, i8* }
+%struct._variable = type { i8*, i8*, void (i8*)*, %struct._variable* }
+%struct.pg_result = type opaque
+
+ at pset = external global %struct._psqlSettings
+
+define signext i8 @do_lo_list() nounwind optsize ssp {
+bb:
+  %myopt = alloca %struct.printQueryOpt, align 4
+  %tmp = bitcast %struct.printQueryOpt* %myopt to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %tmp, i8* bitcast (%struct.printQueryOpt* getelementptr inbounds (%struct._psqlSettings* @pset, i32 0, i32 4) to i8*), i32 76, i32 4, i1 false)
+  ret i8 0
+}
+
+declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind