Thanks to sabre for pointing out that we were incorrectly codegen'ing

int test(int x) { return 32768 - x; }

Fixed by teaching the function that checks a constant's validity to be used
as an immediate argument about subtract-from instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17476 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPC32ISelSimple.cpp b/lib/Target/PowerPC/PPC32ISelSimple.cpp
index d0406c7e402f26bf0adc2a634aeb696a5f3fdbda..5314dada04a5d90e195169a88fe49c36169fc01d 100644 (file)
--- a/lib/Target/PowerPC/PPC32ISelSimple.cpp
+++ b/lib/Target/PowerPC/PPC32ISelSimple.cpp
@@ -536,8 +536,11 @@ bool PPC32ISel::canUseAsImmediateForOpcode(ConstantInt *CI, unsigned Opcode,
     else
       return false;
   }
+
+  // Treat subfic like addi for the purposes of constant validation
+  if (Opcode == 5) Opcode = 0;
       
-  // ADDI, Compare, and non-indexed Load take SIMM
+  // addi, subfic, compare, and non-indexed load take SIMM
   bool cond1 = (Opcode < 2)
     && ((int32_t)CI->getRawValue() <= 32767)
     && ((int32_t)CI->getRawValue() >= -32768);