[MIPS] Fix justify error for small structures

Fix justify error for small structures bigger than 32 bits in fixed
arguments for MIPS64 big endian. There was a problem when small structures
are passed as fixed arguments. The structures that are bigger than 32 bits
but smaller than 64 bits were not left justified properly on MIPS64 big
endian. This is fixed by shifting the value to make it left justified when
appropriate.

Patch by Aleksandar Beserminji.

Differential Revision: http://reviews.llvm.org/D8174

llvm-svn: 232382

2 files changed, 81 insertions, 1 deletions

diff --git a/llvm/lib/Target/Mips/MipsCallingConv.td b/llvm/lib/Target/Mips/MipsCallingConv.td
index abee1851ca2..dcd88f25d25 100644
--- a/llvm/lib/Target/Mips/MipsCallingConv.td
+++ b/llvm/lib/Target/Mips/MipsCallingConv.td
@@ -123,7 +123,7 @@ def CC_MipsN_SoftFloat : CallingConv<[
 ]>;
 
 def CC_MipsN : CallingConv<[
-  CCIfType<[i8, i16, i32],
+  CCIfType<[i8, i16, i32, i64],
       CCIfSubtargetNot<"isLittle()",
           CCIfInReg<CCPromoteToUpperBitsInType<i64>>>>,
 
diff --git a/llvm/test/CodeGen/Mips/cconv/arguments-small-structures-bigger-than-32bits.ll b/llvm/test/CodeGen/Mips/cconv/arguments-small-structures-bigger-than-32bits.ll
new file mode 100644
index 00000000000..087a0515f37
--- /dev/null
+++ b/llvm/test/CodeGen/Mips/cconv/arguments-small-structures-bigger-than-32bits.ll
@@ -0,0 +1,80 @@
+; RUN: llc < %s -march=mips64   -target-abi n64 -mcpu=mips64r2 | FileCheck %s -check-prefix=ALL -check-prefix=MIPSEB
+; RUN: llc < %s -march=mips64el -target-abi n64 -mcpu=mips64r2 | FileCheck %s -check-prefix=ALL -check-prefix=MIPSEL
+; RUN: llc < %s -march=mips64   -target-abi n32 -mcpu=mips64r2 | FileCheck %s -check-prefix=ALL -check-prefix=MIPSEB
+; RUN: llc < %s -march=mips64el -target-abi n32 -mcpu=mips64r2 | FileCheck %s -check-prefix=ALL -check-prefix=MIPSEL
+
+; #include <stdio.h>
+; 
+; struct S1 {
+;   char x1;
+;   short x2;
+;   char x3;
+; };
+; 
+; struct S2 {
+;   char x1;
+;   char x2;
+;   char x3;
+;   char x4;
+;   char x5;
+; };
+; 
+; void fS1(struct S1 s);
+; void fS2(struct S2 s);
+; 
+; void f1() {
+;   struct S1 s1_1;
+;   fS1(s1_1);
+; }
+; 
+; void f2() {
+;   struct S2 s2_1;
+;   fS2(s2_1);
+; }
+; 
+; int main() {
+;   f1();
+;   f2();
+; }
+
+%struct.S1 = type { i8, i16, i8 }
+%struct.S2 = type { i8, i8, i8, i8, i8 }
+
+declare void @fS1(i48 inreg) #1
+declare void @fS2(i40 inreg) #1
+
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1) #2
+
+define void @f1() #0 {
+entry:
+  %s1_1 = alloca %struct.S1, align 2
+  %s1_1.coerce = alloca { i48 }
+  %0 = bitcast { i48 }* %s1_1.coerce to i8*
+  %1 = bitcast %struct.S1* %s1_1 to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %1, i64 6, i32 0, i1 false)
+  %2 = getelementptr { i48 }, { i48 }* %s1_1.coerce, i32 0, i32 0
+  %3 = load i48, i48* %2, align 1
+  call void @fS1(i48 inreg %3)
+  ret void
+ ; ALL-LABEL: f1:
+
+ ; MIPSEB:       dsll $[[R1:[0-9]+]], $[[R2:[0-9]+]], 16
+ ; MIPSEL-NOT:   dsll $[[R1:[0-9]+]], $[[R2:[0-9]+]], 16
+}
+
+define void @f2() #0 {
+entry:
+  %s2_1 = alloca %struct.S2, align 1
+  %s2_1.coerce = alloca { i40 }
+  %0 = bitcast { i40 }* %s2_1.coerce to i8*
+  %1 = bitcast %struct.S2* %s2_1 to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %1, i64 5, i32 0, i1 false)
+  %2 = getelementptr { i40 }, { i40 }* %s2_1.coerce, i32 0, i32 0
+  %3 = load i40, i40* %2, align 1
+  call void @fS2(i40 inreg %3)
+  ret void
+ ; ALL-LABEL: f2:
+
+ ; MIPSEB:       dsll $[[R1:[0-9]+]], $[[R2:[0-9]+]], 24
+ ; MIPSEL-NOT:   dsll $[[R1:[0-9]+]], $[[R2:[0-9]+]], 24
+}