[SystemZ] Temporarily disable high VFs with integer div/rem.

Until mischeduler is clever enough to avoid spilling in a vectorized loop
with many (scalar) DLRs it is better to avoid high vectorization factors (8
and above).

llvm-svn: 344129

2 files changed, 42 insertions, 32 deletions

diff --git a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
index 6efd7f66303..6f553d5bed3 100644
--- a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
@@ -401,6 +401,13 @@ int SystemZTTIImpl::getArithmeticInstrCost(
     if (SDivPow2)
       return (NumVectors * SDivCostEstimate);
 
+    // Temporary hack: disable high vectorization factors with integer
+    // division/remainder, which will get scalarized and handled with GR128
+    // registers. The mischeduler is not clever enough to avoid spilling yet.
+    if ((Opcode == Instruction::UDiv || Opcode == Instruction::SDiv ||
+         Opcode == Instruction::URem || Opcode == Instruction::SRem) && VF > 4)
+      return 1000;
+
     // These FP operations are supported with a single vector instruction for
     // double (base implementation assumes float generally costs 2). For
     // FP128, the scalar cost is 1, and there is no overhead since the values
diff --git a/llvm/test/Analysis/CostModel/SystemZ/int-arith.ll b/llvm/test/Analysis/CostModel/SystemZ/int-arith.ll
index 518c9b01e4e..3ecf4342b94 100644
--- a/llvm/test/Analysis/CostModel/SystemZ/int-arith.ll
+++ b/llvm/test/Analysis/CostModel/SystemZ/int-arith.ll
@@ -2,6 +2,9 @@
 ;
 ; Note: The scalarized vector instructions costs are not including any
 ; extracts, due to the undef operands.
+;
+; Note: Vectorization of division/remainder is temporarily disabled for high
+; vectorization factors by returning 1000.
 
 define void @add() {
   %res0 = add i8 undef, undef
@@ -175,14 +178,14 @@ define void @sdiv() {
 ; CHECK: Cost Model: Found an estimated cost of 20 for instruction:   %res9 = sdiv <4 x i16> undef, undef
 ; CHECK: Cost Model: Found an estimated cost of 12 for instruction:   %res10 = sdiv <4 x i32> undef, undef
 ; CHECK: Cost Model: Found an estimated cost of 6 for instruction:   %res11 = sdiv <4 x i64> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 40 for instruction:   %res12 = sdiv <8 x i8> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 40 for instruction:   %res13 = sdiv <8 x i16> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 24 for instruction:   %res14 = sdiv <8 x i32> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 12 for instruction:   %res15 = sdiv <8 x i64> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 80 for instruction:   %res16 = sdiv <16 x i8> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 80 for instruction:   %res17 = sdiv <16 x i16> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 48 for instruction:   %res18 = sdiv <16 x i32> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 24 for instruction:   %res19 = sdiv <16 x i64> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res12 = sdiv <8 x i8> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res13 = sdiv <8 x i16> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res14 = sdiv <8 x i32> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res15 = sdiv <8 x i64> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res16 = sdiv <16 x i8> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res17 = sdiv <16 x i16> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res18 = sdiv <16 x i32> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res19 = sdiv <16 x i64> undef, undef
 
   ret void;
 }
@@ -221,14 +224,14 @@ define void @srem() {
 ; CHECK: Cost Model: Found an estimated cost of 20 for instruction:   %res9 = srem <4 x i16> undef, undef
 ; CHECK: Cost Model: Found an estimated cost of 12 for instruction:   %res10 = srem <4 x i32> undef, undef
 ; CHECK: Cost Model: Found an estimated cost of 6 for instruction:   %res11 = srem <4 x i64> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 40 for instruction:   %res12 = srem <8 x i8> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 40 for instruction:   %res13 = srem <8 x i16> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 24 for instruction:   %res14 = srem <8 x i32> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 12 for instruction:   %res15 = srem <8 x i64> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 80 for instruction:   %res16 = srem <16 x i8> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 80 for instruction:   %res17 = srem <16 x i16> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 48 for instruction:   %res18 = srem <16 x i32> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 24 for instruction:   %res19 = srem <16 x i64> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res12 = srem <8 x i8> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res13 = srem <8 x i16> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res14 = srem <8 x i32> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res15 = srem <8 x i64> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res16 = srem <16 x i8> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res17 = srem <16 x i16> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res18 = srem <16 x i32> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res19 = srem <16 x i64> undef, undef
 
   ret void;
 }
@@ -267,14 +270,14 @@ define void @udiv() {
 ; CHECK: Cost Model: Found an estimated cost of 20 for instruction:   %res9 = udiv <4 x i16> undef, undef
 ; CHECK: Cost Model: Found an estimated cost of 12 for instruction:   %res10 = udiv <4 x i32> undef, undef
 ; CHECK: Cost Model: Found an estimated cost of 10 for instruction:   %res11 = udiv <4 x i64> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 40 for instruction:   %res12 = udiv <8 x i8> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 40 for instruction:   %res13 = udiv <8 x i16> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 24 for instruction:   %res14 = udiv <8 x i32> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 20 for instruction:   %res15 = udiv <8 x i64> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 80 for instruction:   %res16 = udiv <16 x i8> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 80 for instruction:   %res17 = udiv <16 x i16> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 48 for instruction:   %res18 = udiv <16 x i32> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 40 for instruction:   %res19 = udiv <16 x i64> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res12 = udiv <8 x i8> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res13 = udiv <8 x i16> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res14 = udiv <8 x i32> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res15 = udiv <8 x i64> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res16 = udiv <16 x i8> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res17 = udiv <16 x i16> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res18 = udiv <16 x i32> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res19 = udiv <16 x i64> undef, undef
 
   ret void;
 }
@@ -313,14 +316,14 @@ define void @urem() {
 ; CHECK: Cost Model: Found an estimated cost of 20 for instruction:   %res9 = urem <4 x i16> undef, undef
 ; CHECK: Cost Model: Found an estimated cost of 12 for instruction:   %res10 = urem <4 x i32> undef, undef
 ; CHECK: Cost Model: Found an estimated cost of 10 for instruction:   %res11 = urem <4 x i64> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 40 for instruction:   %res12 = urem <8 x i8> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 40 for instruction:   %res13 = urem <8 x i16> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 24 for instruction:   %res14 = urem <8 x i32> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 20 for instruction:   %res15 = urem <8 x i64> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 80 for instruction:   %res16 = urem <16 x i8> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 80 for instruction:   %res17 = urem <16 x i16> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 48 for instruction:   %res18 = urem <16 x i32> undef, undef
-; CHECK: Cost Model: Found an estimated cost of 40 for instruction:   %res19 = urem <16 x i64> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res12 = urem <8 x i8> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res13 = urem <8 x i16> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res14 = urem <8 x i32> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res15 = urem <8 x i64> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res16 = urem <16 x i8> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res17 = urem <16 x i16> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res18 = urem <16 x i32> undef, undef
+; CHECK: Cost Model: Found an estimated cost of 1000 for instruction:   %res19 = urem <16 x i64> undef, undef
 
   ret void;
 }