This patch addresses a PPC64 ELF issue with passing parameters consisting of

structs having size 3, 5, 6, or 7.  Such a struct must be passed and received
as right-justified within its register or memory slot.  The problem is only
present for structs that are passed in registers.

Previously, as part of a patch handling all structs of size less than 8, I
added logic to rotate the incoming register so that the struct was left-
justified prior to storing the whole register.  This was incorrect because
the address of the parameter had already been adjusted earlier to point to
the right-adjusted value in the storage slot.  Essentially I had accidentally
accounted for the right-adjustment twice.

In this patch, I removed the incorrect logic and reorganized the code to make
the flow clearer.

The removal of the rotates changes the expected code generation, so test case
structsinregs.ll has been modified to reflect this.  I also added a new test
case, jaggedstructs.ll, to demonstrate that structs of these sizes can now
be properly received and passed.

I've built and tested the code on powerpc64-unknown-linux-gnu with no new
regressions.  I also ran the GCC compatibility test suite and verified that
earlier problems with these structs are now resolved, with no new regressions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166680 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 51 insertions, 7 deletions

diff --git a/test/CodeGen/PowerPC/jaggedstructs.ll b/test/CodeGen/PowerPC/jaggedstructs.ll
new file mode 100644
index 0000000000..62aa7cf929
--- /dev/null
+++ b/test/CodeGen/PowerPC/jaggedstructs.ll
@@ -0,0 +1,48 @@
+; RUN: llc -mcpu=pwr7 -O0 < %s | FileCheck %s
+
+; This tests receiving and re-passing parameters consisting of structures
+; of size 3, 5, 6, and 7.  They are to be found/placed right-adjusted in
+; the parameter registers.
+
+target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v128:128:128-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+
+%struct.S3 = type { [3 x i8] }
+%struct.S5 = type { [5 x i8] }
+%struct.S6 = type { [6 x i8] }
+%struct.S7 = type { [7 x i8] }
+
+define void @test(%struct.S3* byval %s3, %struct.S5* byval %s5, %struct.S6* byval %s6, %struct.S7* byval %s7) nounwind {
+entry:
+  call void @check(%struct.S3* byval %s3, %struct.S5* byval %s5, %struct.S6* byval %s6, %struct.S7* byval %s7)
+  ret void
+}
+
+; CHECK: std 6, 216(1)
+; CHECK: std 5, 208(1)
+; CHECK: std 4, 200(1)
+; CHECK: std 3, 192(1)
+; CHECK: lbz {{[0-9]+}}, 199(1)
+; CHECK: stb {{[0-9]+}}, 55(1)
+; CHECK: lhz {{[0-9]+}}, 197(1)
+; CHECK: sth {{[0-9]+}}, 53(1)
+; CHECK: lbz {{[0-9]+}}, 207(1)
+; CHECK: stb {{[0-9]+}}, 63(1)
+; CHECK: lwz {{[0-9]+}}, 203(1)
+; CHECK: stw {{[0-9]+}}, 59(1)
+; CHECK: lhz {{[0-9]+}}, 214(1)
+; CHECK: sth {{[0-9]+}}, 70(1)
+; CHECK: lwz {{[0-9]+}}, 210(1)
+; CHECK: stw {{[0-9]+}}, 66(1)
+; CHECK: lbz {{[0-9]+}}, 223(1)
+; CHECK: stb {{[0-9]+}}, 79(1)
+; CHECK: lhz {{[0-9]+}}, 221(1)
+; CHECK: sth {{[0-9]+}}, 77(1)
+; CHECK: lwz {{[0-9]+}}, 217(1)
+; CHECK: stw {{[0-9]+}}, 73(1)
+; CHECK: ld 6, 72(1)
+; CHECK: ld 5, 64(1)
+; CHECK: ld 4, 56(1)
+; CHECK: ld 3, 48(1)
+
+declare void @check(%struct.S3* byval, %struct.S5* byval, %struct.S6* byval, %struct.S7* byval)
diff --git a/test/CodeGen/PowerPC/structsinregs.ll b/test/CodeGen/PowerPC/structsinregs.ll
index 43ba13b426..ef706af95d 100644
--- a/test/CodeGen/PowerPC/structsinregs.ll
+++ b/test/CodeGen/PowerPC/structsinregs.ll
@@ -188,17 +188,13 @@ entry:
   %add13 = add nsw i32 %add11, %6
   ret i32 %add13
 
-; CHECK: sldi 9, 9, 8
-; CHECK: sldi 8, 8, 16
-; CHECK: sldi 7, 7, 24
-; CHECK: sldi 5, 5, 40
-; CHECK: stw 6, 76(1)
-; CHECK: sth 4, 62(1)
-; CHECK: stb 3, 55(1)
 ; CHECK: std 9, 96(1)
 ; CHECK: std 8, 88(1)
 ; CHECK: std 7, 80(1)
+; CHECK: stw 6, 76(1)
 ; CHECK: std 5, 64(1)
+; CHECK: sth 4, 62(1)
+; CHECK: stb 3, 55(1)
 ; CHECK: lbz {{[0-9]+}}, 85(1)
 ; CHECK: lbz {{[0-9]+}}, 86(1)
 ; CHECK: lbz {{[0-9]+}}, 83(1)