[PowerPC] Remove canFoldAsLoad from instruction definitions

The PowerPC backend had a number of loads that were marked as canFoldAsLoad
(and I'm partially at fault here for copying around the relevant line of
TableGen definitions without really looking at what it meant). This is not
right; PPC (non-memory) instructions don't support direct memory operands, and
so there is nothing a 'foldable' instruction could be folded into.

Noticed by inspection, no test case.

The one thing we might lose by doing this is ability to fold some loads into
stackmap/patchpoint pseudo-instructions. However, this was untested, and would
not obviously have worked for extending loads, and I'd rather re-add support
for that once it can be tested.

llvm-svn: 231982
diff --git a/llvm/lib/Target/PowerPC/PPCInstr64Bit.td b/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
index 76fa45c..36479e2 100644
--- a/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
+++ b/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
@@ -700,7 +700,7 @@
 
 
 // Sign extending loads.
-let canFoldAsLoad = 1, PPC970_Unit = 2 in {
+let PPC970_Unit = 2 in {
 let Interpretation64Bit = 1, isCodeGenOnly = 1 in
 def LHA8: DForm_1<42, (outs g8rc:$rD), (ins memri:$src),
                   "lha $rD, $src", IIC_LdStLHA,
@@ -756,7 +756,7 @@
 
 let Interpretation64Bit = 1, isCodeGenOnly = 1 in {
 // Zero extending loads.
-let canFoldAsLoad = 1, PPC970_Unit = 2 in {
+let PPC970_Unit = 2 in {
 def LBZ8 : DForm_1<34, (outs g8rc:$rD), (ins memri:$src),
                   "lbz $rD, $src", IIC_LdStLoad,
                   [(set i64:$rD, (zextloadi8 iaddr:$src))]>;
@@ -814,7 +814,7 @@
 
 
 // Full 8-byte loads.
-let canFoldAsLoad = 1, PPC970_Unit = 2 in {
+let PPC970_Unit = 2 in {
 def LD   : DSForm_1<58, 0, (outs g8rc:$rD), (ins memrix:$src),
                     "ld $rD, $src", IIC_LdStLD,
                     [(set i64:$rD, (aligned4load ixaddr:$src))]>, isPPC64;