Index: llvm/trunk/lib/Target/X86/X86TargetMachine.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86TargetMachine.cpp
+++ llvm/trunk/lib/Target/X86/X86TargetMachine.cpp
@@ -73,17 +73,22 @@
   // Some ABIs align 64 bit integers and doubles to 64 bits, others to 32.
   if (TT.isArch64Bit() || TT.isOSWindows() || TT.isOSNaCl())
     Ret += "-i64:64";
+  else if (TT.isOSIAMCU())
+    Ret += "-i64:32-f64:32";
   else
     Ret += "-f64:32:64";
 
   // Some ABIs align long double to 128 bits, others to 32.
-  if (TT.isOSNaCl())
+  if (TT.isOSNaCl() || TT.isOSIAMCU())
     ; // No f80
   else if (TT.isArch64Bit() || TT.isOSDarwin())
     Ret += "-f80:128";
   else
     Ret += "-f80:32";
 
+  if (TT.isOSIAMCU())
+    Ret += "-f128:32";
+
   // The registers can hold 8, 16, 32 or, in x86-64, 64 bits.
   if (TT.isArch64Bit())
     Ret += "-n8:16:32:64";
@@ -91,7 +96,7 @@
     Ret += "-n8:16:32";
 
   // The stack is aligned to 32 bits on some ABIs and 128 bits on others.
-  if (!TT.isArch64Bit() && TT.isOSWindows())
+  if ((!TT.isArch64Bit() && TT.isOSWindows()) || TT.isOSIAMCU())
     Ret += "-a:0:32-S32";
   else
     Ret += "-S128";
Index: llvm/trunk/test/CodeGen/X86/mcu-abi.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/mcu-abi.ll
+++ llvm/trunk/test/CodeGen/X86/mcu-abi.ll
@@ -82,6 +82,8 @@
   ret i32 %i1
 }
 
+%struct.S = type { i8 }
+
 ; CHECK-LABEL: test_lib_args:
 ; CHECK: movl %edx, %eax
 ; CHECK: calll __fixsfsi
@@ -108,5 +110,50 @@
 
 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture readonly, i32, i32, i1) #1
 
+; CHECK-LABEL: test_alignment_d:
+; CHECK-NOT: andl  {{.+}}, %esp
+define void @test_alignment_d() #0 {
+entry:
+  %d = alloca double
+  store double 2.000000e+00, double* %d
+  call void @food(double* inreg %d) 
+  ret void
+}
+
+; CHECK-LABEL: test_alignment_i:
+; CHECK-NOT: andl  {{.+}}, %esp
+define void @test_alignment_i() #0 {
+entry:
+  %i = alloca i64
+  store i64 2, i64* %i
+  call void @fooi(i64* inreg %i) 
+  ret void
+}
+
+
+; CHECK-LABEL: test_alignment_s:
+; CHECK-NOT: andl  {{.+}}, %esp
+define void @test_alignment_s() #0 {
+  %s = alloca %struct.S, align 4
+  call void @foos(%struct.S* inreg %s) 
+  ret void
+}
+
+
+; CHECK-LABEL: test_alignment_fp:
+; CHECK-NOT: andl  {{.+}}, %esp
+define void @test_alignment_fp() #0 {
+entry:
+  %f = alloca fp128
+  store fp128 0xL00000000000000004000000000000000, fp128* %f
+  call void @foofp(fp128* inreg %f)
+  ret void
+}
+
+declare void @food(double* inreg)
+declare void @fooi(i64* inreg)
+declare void @foos(%struct.S* inreg)
+declare void @foofp(fp128* inreg)
+
 attributes #0 = { nounwind "use-soft-float"="true"}
 attributes #1 = { nounwind argmemonly }