[PATCH] D30387: [X86] Fix SmallVector sizes in constant pool shuffle decoding to avoid heap allocation

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.

Some of the vectors are under sized to avoid heap allocation. In one case the vector was oversized.

Not sure if 64 uint64_ts is maybe too much stack space.


https://reviews.llvm.org/D30387

Files:
  lib/Target/X86/X86ShuffleDecodeConstantPool.cpp


Index: lib/Target/X86/X86ShuffleDecodeConstantPool.cpp
===================================================================
--- lib/Target/X86/X86ShuffleDecodeConstantPool.cpp
+++ lib/Target/X86/X86ShuffleDecodeConstantPool.cpp
@@ -104,7 +104,7 @@
 
   // The shuffle mask requires a byte vector.
   SmallBitVector UndefElts;
-  SmallVector<uint64_t, 32> RawMask;
+  SmallVector<uint64_t, 64> RawMask;
   if (!extractConstantMask(C, 8, UndefElts, RawMask))
     return;
 
@@ -145,7 +145,7 @@
 
   // The shuffle mask requires elements the same size as the target.
   SmallBitVector UndefElts;
-  SmallVector<uint64_t, 8> RawMask;
+  SmallVector<uint64_t, 16> RawMask;
   if (!extractConstantMask(C, ElSize, UndefElts, RawMask))
     return;
 
@@ -231,7 +231,7 @@
 
   // The shuffle mask requires a byte vector.
   SmallBitVector UndefElts;
-  SmallVector<uint64_t, 32> RawMask;
+  SmallVector<uint64_t, 16> RawMask;
   if (!extractConstantMask(C, 8, UndefElts, RawMask))
     return;
 
@@ -286,7 +286,7 @@
 
   // The shuffle mask requires elements the same size as the target.
   SmallBitVector UndefElts;
-  SmallVector<uint64_t, 8> RawMask;
+  SmallVector<uint64_t, 64> RawMask;
   if (!extractConstantMask(C, ElSize, UndefElts, RawMask))
     return;
 
@@ -314,7 +314,7 @@
 
   // The shuffle mask requires elements the same size as the target.
   SmallBitVector UndefElts;
-  SmallVector<uint64_t, 8> RawMask;
+  SmallVector<uint64_t, 64> RawMask;
   if (!extractConstantMask(C, ElSize, UndefElts, RawMask))
     return;
 


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