[llvm] r304540 - [X86] Don't fold into memory operands into insertps in the generated folding tables.

[Benjamin Kramer via llvm-commits]

Author: d0k
Date: Fri Jun  2 05:50:22 2017
New Revision: 304540

URL: http://llvm.org/viewvc/llvm-project?rev=304540&view=rev
Log:
[X86] Don't fold into memory operands into insertps in the generated folding tables.

insertps behaves differently, the register form selects from an input
register based on the immediate operand while the memory form just loads
the given address. We have custom code to change the immediate in cases
where that's legal, so completely remove insertps from the generated
tables.

Modified:
    llvm/trunk/test/CodeGen/X86/stack-folding-fp-avx1.ll
    llvm/trunk/utils/TableGen/X86FoldTablesEmitter.cpp

Modified: llvm/trunk/test/CodeGen/X86/stack-folding-fp-avx1.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/stack-folding-fp-avx1.ll?rev=304540&r1=304539&r2=304540&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/stack-folding-fp-avx1.ll (original)
+++ llvm/trunk/test/CodeGen/X86/stack-folding-fp-avx1.ll Fri Jun  2 05:50:22 2017
@@ -1926,5 +1926,19 @@ define <8 x float> @stack_fold_xorps_ymm
   ret <8 x float> %6
 }
 
+define <4 x float> @stack_nofold_insertps(<8 x float> %a0, <8 x float> %a1) {
+; Cannot fold this without changing the immediate.
+; CHECK-LABEL: stack_nofold_insertps
+; CHECK:       32-byte Spill
+; CHECK:       nop
+; CHECK:       32-byte Reload
+; CHECK:       vinsertps $179, {{%xmm., %xmm., %xmm.}}
+  %1 = tail call <2 x i64> asm sideeffect "nop", "=x,~{xmm2},~{xmm3},~{xmm4},~{xmm5},~{xmm6},~{xmm7},~{xmm8},~{xmm9},~{xmm10},~{xmm11},~{xmm12},~{xmm13},~{xmm14},~{xmm15},~{flags}"()
+  %v0 = shufflevector <8 x float> %a0, <8 x float> undef, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
+  %v1 = shufflevector <8 x float> %a1, <8 x float> undef, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
+  %res = call <4 x float> @llvm.x86.sse41.insertps(<4 x float> %v0, <4 x float> %v1, i8 179)
+  ret <4 x float> %res
+}
+
 attributes #0 = { "unsafe-fp-math"="false" }
 attributes #1 = { "unsafe-fp-math"="true" }

Modified: llvm/trunk/utils/TableGen/X86FoldTablesEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/X86FoldTablesEmitter.cpp?rev=304540&r1=304539&r2=304540&view=diff
==============================================================================
--- llvm/trunk/utils/TableGen/X86FoldTablesEmitter.cpp (original)
+++ llvm/trunk/utils/TableGen/X86FoldTablesEmitter.cpp Fri Jun  2 05:50:22 2017
@@ -101,6 +101,11 @@ const char *const NoFoldSet[] = {
     "BTS16rr", "BTS32rr", "BTS64rr",
     "BTS16mr", "BTS32mr", "BTS64mr",
 
+    // insertps cannot be folded without adjusting the immediate. There's custom
+    // code to handle it in X86InstrInfo.cpp, ignore it here.
+    "INSERTPSrr", "INSERTPSrm",
+    "VINSERTPSrr", "VINSERTPSrm", "VINSERTPSZrr", "VINSERTPSZrm",
+
     // Memory folding is enabled only when optimizing for size by DAG
     // patterns only. (issue detailed in D28744 review)
     "VCVTSS2SDrm",            "VCVTSS2SDrr",