[SelectionDAG] Allow targets to specify legality of extloads' result

type (in addition to the memory type).

The *LoadExt* legalization handling used to only have one type, the
memory type.  This forced users to assume that as long as the extload
for the memory type was declared legal, and the result type was legal,
the whole extload was legal.

However, this isn't always the case.  For instance, on X86, with AVX,
this is legal:
    v4i32 load, zext from v4i8
but this isn't:
    v4i64 load, zext from v4i8
Whereas v4i64 is (arguably) legal, even without AVX2.

Note that the same thing was done a while ago for truncstores (r46140),
but I assume no one needed it yet for extloads, so here we go.

Calls to getLoadExtAction were changed to add the value type, found
manually in the surrounding code.

Calls to setLoadExtAction were mechanically changed, by wrapping the
call in a loop, to match previous behavior.  The loop iterates over
the MVT subrange corresponding to the memory type (FP vectors, etc...).
I also pulled neighboring setTruncStoreActions into some of the loops;
those shouldn't make a difference, as the additional types are illegal.
(e.g., i128->i1 truncstores on PPC.)

No functional change intended.

Differential Revision: http://reviews.llvm.org/D6532

llvm-svn: 225421

1 files changed, 39 insertions, 26 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 1928ef0b9ca..29321472e25 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -292,7 +292,8 @@ void X86TargetLowering::resetOperationActions() {
   if (Subtarget->is64Bit())
     addRegisterClass(MVT::i64, &X86::GR64RegClass);
 
-  setLoadExtAction(ISD::SEXTLOAD, MVT::i1, Promote);
+  for (MVT VT : MVT::integer_valuetypes())
+    setLoadExtAction(ISD::SEXTLOAD, VT, MVT::i1, Promote);
 
   // We don't accept any truncstore of integer registers.
   setTruncStoreAction(MVT::i64, MVT::i32, Expand);
@@ -517,7 +518,9 @@ void X86TargetLowering::resetOperationActions() {
   setOperationAction(ISD::FP_TO_FP16, MVT::f64, Expand);
   setOperationAction(ISD::FP_TO_FP16, MVT::f80, Expand);
 
-  setLoadExtAction(ISD::EXTLOAD, MVT::f16, Expand);
+  setLoadExtAction(ISD::EXTLOAD, MVT::f32, MVT::f16, Expand);
+  setLoadExtAction(ISD::EXTLOAD, MVT::f64, MVT::f16, Expand);
+  setLoadExtAction(ISD::EXTLOAD, MVT::f80, MVT::f16, Expand);
   setTruncStoreAction(MVT::f32, MVT::f16, Expand);
   setTruncStoreAction(MVT::f64, MVT::f16, Expand);
   setTruncStoreAction(MVT::f80, MVT::f16, Expand);
@@ -870,16 +873,18 @@ void X86TargetLowering::resetOperationActions() {
     setOperationAction(ISD::ANY_EXTEND, VT, Expand);
     setOperationAction(ISD::VSELECT, VT, Expand);
     setOperationAction(ISD::SELECT_CC, VT, Expand);
-    for (MVT InnerVT : MVT::vector_valuetypes())
-      setTruncStoreAction(VT, InnerVT, Expand);
-    setLoadExtAction(ISD::SEXTLOAD, VT, Expand);
-    setLoadExtAction(ISD::ZEXTLOAD, VT, Expand);
+    for (MVT InnerVT : MVT::vector_valuetypes()) {
+      setTruncStoreAction(InnerVT, VT, Expand);
 
-    // N.b. ISD::EXTLOAD legality is basically ignored except for i1-like types,
-    // we have to deal with them whether we ask for Expansion or not. Setting
-    // Expand causes its own optimisation problems though, so leave them legal.
-    if (VT.getVectorElementType() == MVT::i1)
-      setLoadExtAction(ISD::EXTLOAD, VT, Expand);
+      setLoadExtAction(ISD::SEXTLOAD, InnerVT, VT, Expand);
+      setLoadExtAction(ISD::ZEXTLOAD, InnerVT, VT, Expand);
+
+      // N.b. ISD::EXTLOAD legality is basically ignored except for i1-like types,
+      // we have to deal with them whether we ask for Expansion or not. Setting
+      // Expand causes its own optimisation problems though, so leave them legal.
+      if (VT.getVectorElementType() == MVT::i1)
+        setLoadExtAction(ISD::EXTLOAD, InnerVT, VT, Expand);
+    }
   }
 
   // FIXME: In order to prevent SSE instructions being expanded to MMX ones
@@ -1009,15 +1014,17 @@ void X86TargetLowering::resetOperationActions() {
     // memory vector types which we can load as a scalar (or sequence of
     // scalars) and extend in-register to a legal 128-bit vector type. For sext
     // loads these must work with a single scalar load.
-    setLoadExtAction(ISD::SEXTLOAD, MVT::v4i8, Custom);
-    setLoadExtAction(ISD::SEXTLOAD, MVT::v4i16, Custom);
-    setLoadExtAction(ISD::SEXTLOAD, MVT::v8i8, Custom);
-    setLoadExtAction(ISD::EXTLOAD, MVT::v2i8, Custom);
-    setLoadExtAction(ISD::EXTLOAD, MVT::v2i16, Custom);
-    setLoadExtAction(ISD::EXTLOAD, MVT::v2i32, Custom);
-    setLoadExtAction(ISD::EXTLOAD, MVT::v4i8, Custom);
-    setLoadExtAction(ISD::EXTLOAD, MVT::v4i16, Custom);
-    setLoadExtAction(ISD::EXTLOAD, MVT::v8i8, Custom);
+    for (MVT VT : MVT::integer_vector_valuetypes()) {
+      setLoadExtAction(ISD::SEXTLOAD, VT, MVT::v4i8, Custom);
+      setLoadExtAction(ISD::SEXTLOAD, VT, MVT::v4i16, Custom);
+      setLoadExtAction(ISD::SEXTLOAD, VT, MVT::v8i8, Custom);
+      setLoadExtAction(ISD::EXTLOAD, VT, MVT::v2i8, Custom);
+      setLoadExtAction(ISD::EXTLOAD, VT, MVT::v2i16, Custom);
+      setLoadExtAction(ISD::EXTLOAD, VT, MVT::v2i32, Custom);
+      setLoadExtAction(ISD::EXTLOAD, VT, MVT::v4i8, Custom);
+      setLoadExtAction(ISD::EXTLOAD, VT, MVT::v4i16, Custom);
+      setLoadExtAction(ISD::EXTLOAD, VT, MVT::v8i8, Custom);
+    }
 
     setOperationAction(ISD::BUILD_VECTOR,       MVT::v2f64, Custom);
     setOperationAction(ISD::BUILD_VECTOR,       MVT::v2i64, Custom);
@@ -1070,7 +1077,8 @@ void X86TargetLowering::resetOperationActions() {
     setOperationAction(ISD::FP_EXTEND,          MVT::v2f32, Custom);
     setOperationAction(ISD::FP_ROUND,           MVT::v2f32, Custom);
 
-    setLoadExtAction(ISD::EXTLOAD,              MVT::v2f32, Legal);
+    for (MVT VT : MVT::fp_vector_valuetypes())
+      setLoadExtAction(ISD::EXTLOAD, VT, MVT::v2f32, Legal);
 
     setOperationAction(ISD::BITCAST,            MVT::v2i32, Custom);
     setOperationAction(ISD::BITCAST,            MVT::v4i16, Custom);
@@ -1114,9 +1122,11 @@ void X86TargetLowering::resetOperationActions() {
 
     // SSE41 brings specific instructions for doing vector sign extend even in
     // cases where we don't have SRA.
-    setLoadExtAction(ISD::SEXTLOAD, MVT::v2i8, Custom);
-    setLoadExtAction(ISD::SEXTLOAD, MVT::v2i16, Custom);
-    setLoadExtAction(ISD::SEXTLOAD, MVT::v2i32, Custom);
+    for (MVT VT : MVT::integer_vector_valuetypes()) {
+      setLoadExtAction(ISD::SEXTLOAD, VT, MVT::v2i8, Custom);
+      setLoadExtAction(ISD::SEXTLOAD, VT, MVT::v2i16, Custom);
+      setLoadExtAction(ISD::SEXTLOAD, VT, MVT::v2i32, Custom);
+    }
 
     // i8 and i16 vectors are custom because the source register and source
     // source memory operand types are not the same width.  f32 vectors are
@@ -1212,7 +1222,8 @@ void X86TargetLowering::resetOperationActions() {
     setOperationAction(ISD::UINT_TO_FP,         MVT::v8i8,  Custom);
     setOperationAction(ISD::UINT_TO_FP,         MVT::v8i16, Custom);
 
-    setLoadExtAction(ISD::EXTLOAD,              MVT::v4f32, Legal);
+    for (MVT VT : MVT::fp_vector_valuetypes())
+      setLoadExtAction(ISD::EXTLOAD, VT, MVT::v4f32, Legal);
 
     setOperationAction(ISD::SRL,               MVT::v16i16, Custom);
     setOperationAction(ISD::SRL,               MVT::v32i8, Custom);
@@ -1378,12 +1389,14 @@ void X86TargetLowering::resetOperationActions() {
     addRegisterClass(MVT::v8i1,   &X86::VK8RegClass);
     addRegisterClass(MVT::v16i1,  &X86::VK16RegClass);
 
+    for (MVT VT : MVT::fp_vector_valuetypes())
+      setLoadExtAction(ISD::EXTLOAD, VT, MVT::v8f32, Legal);
+
     setOperationAction(ISD::BR_CC,              MVT::i1,    Expand);
     setOperationAction(ISD::SETCC,              MVT::i1,    Custom);
     setOperationAction(ISD::XOR,                MVT::i1,    Legal);
     setOperationAction(ISD::OR,                 MVT::i1,    Legal);
     setOperationAction(ISD::AND,                MVT::i1,    Legal);
-    setLoadExtAction(ISD::EXTLOAD,              MVT::v8f32, Legal);
     setOperationAction(ISD::LOAD,               MVT::v16f32, Legal);
     setOperationAction(ISD::LOAD,               MVT::v8f64, Legal);
     setOperationAction(ISD::LOAD,               MVT::v8i64, Legal);