[RISCV][CostModel] Remove cost of icmp inst in icmp+select with SFB. (#…

…91158)

With ShortFowrardBranchOpt(SFB) or ConditionalMoveFusion, scalar
ICmp and scalar Select instructions will lower to SELECT_CC
and lower to PseudoCCMOVGPR which will generate a conditional
branch instruction and a move instruction.
The cost of scalar (ICmp + Select) = (0 + Select instruction cost)

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp

@@ -14,9 +14,11 @@
 #include "llvm/CodeGen/CostTable.h"
 #include "llvm/CodeGen/TargetLowering.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/IR/PatternMatch.h"
 #include <cmath>
 #include <optional>
 using namespace llvm;
+using namespace llvm::PatternMatch;
 
 #define DEBUG_TYPE "riscvtti"
 
@@ -1469,6 +1471,21 @@ InstructionCost RISCVTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
     }
   }
 
+  // With ShortForwardBranchOpt or ConditionalMoveFusion, scalar icmp + select
+  // instructions will lower to SELECT_CC and lower to PseudoCCMOVGPR which will
+  // generate a conditional branch + mv. The cost of scalar (icmp + select) will
+  // be (0 + select instr cost).
+  if (ST->hasConditionalMoveFusion() && I && isa<ICmpInst>(I) &&
+      ValTy->isIntegerTy() && !I->user_empty()) {
+    if (all_of(I->users(), [&](const User *U) {
+          return match(U, m_Select(m_Specific(I), m_Value(), m_Value())) &&
+                 U->getType()->isIntegerTy() &&
+                 !isa<ConstantData>(U->getOperand(1)) &&
+                 !isa<ConstantData>(U->getOperand(2));
+        }))
+      return 0;
+  }
+
   // TODO: Add cost for scalar type.
 
   return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind, I);

llvm/test/Analysis/CostModel/RISCV/cmp-select.ll

@@ -0,0 +1,258 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
+; RUN: opt < %s -mtriple=riscv64 -mattr=+v,+f,+short-forward-branch-opt -passes="print<cost-model>" -cost-kind=throughput 2>&1 -disable-output | FileCheck %s --check-prefixes=SFB64
+; RUN: opt < %s -mtriple=riscv64 -mattr=+v,+f -passes="print<cost-model>" -cost-kind=throughput 2>&1 -disable-output | FileCheck %s --check-prefixes=RV64
+
+define i32 @icmp-iselect(i64 %ca, i64 %cb, i32 %a, i32 %b) {
+; SFB64-LABEL: 'icmp-iselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %cmp1 = icmp slt i64 %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select i1 %cmp1, i32 %a, i32 %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 %select1
+;
+; RV64-LABEL: 'icmp-iselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %cmp1 = icmp slt i64 %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select i1 %cmp1, i32 %a, i32 %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 %select1
+;
+  %cmp1 = icmp slt i64 %ca, %cb
+  %select1 = select i1 %cmp1, i32 %a, i32 %b
+  ret i32 %select1
+}
+
+define i32 @icmp-iselects(i64 %ca, i64 %cb, i32 %a, i32 %b, i32 %c) {
+; SFB64-LABEL: 'icmp-iselects'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %cmp1 = icmp slt i64 %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select i1 %cmp1, i32 %a, i32 %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select2 = select i1 %cmp1, i32 %a, i32 %c
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %ret = add i32 %select1, %select2
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 %ret
+;
+; RV64-LABEL: 'icmp-iselects'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %cmp1 = icmp slt i64 %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select i1 %cmp1, i32 %a, i32 %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select2 = select i1 %cmp1, i32 %a, i32 %c
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %ret = add i32 %select1, %select2
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 %ret
+;
+  %cmp1 = icmp slt i64 %ca, %cb
+  %select1 = select i1 %cmp1, i32 %a, i32 %b
+  %select2 = select i1 %cmp1, i32 %a, i32 %c
+  %ret = add i32 %select1, %select2
+  ret i32 %ret
+}
+
+define i32 @icmp-ifselects(i64 %ca, i64 %cb, i32 %a, i32 %b, float %c, float %d) {
+; SFB64-LABEL: 'icmp-ifselects'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %cmp1 = icmp slt i64 %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select i1 %cmp1, i32 %a, i32 %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select2 = select i1 %cmp1, float %c, float %d
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %selectint = fptosi float %select2 to i32
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %ret = add i32 %select1, %selectint
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 %ret
+;
+; RV64-LABEL: 'icmp-ifselects'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %cmp1 = icmp slt i64 %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select i1 %cmp1, i32 %a, i32 %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select2 = select i1 %cmp1, float %c, float %d
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %selectint = fptosi float %select2 to i32
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %ret = add i32 %select1, %selectint
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 %ret
+;
+  %cmp1 = icmp slt i64 %ca, %cb
+  %select1 = select i1 %cmp1, i32 %a, i32 %b
+  %select2 = select i1 %cmp1, float %c, float %d
+  %selectint = fptosi float %select2 to i32
+  %ret = add i32 %select1, %selectint
+  ret i32 %ret
+}
+
+define i32 @constant-icmp-iselect(i64 %ca, i64 %cb, i32 %a) {
+; SFB64-LABEL: 'constant-icmp-iselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %cmp1 = icmp slt i64 %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select i1 %cmp1, i32 %a, i32 7
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 %select1
+;
+; RV64-LABEL: 'constant-icmp-iselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %cmp1 = icmp slt i64 %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select i1 %cmp1, i32 %a, i32 7
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 %select1
+;
+  %cmp1 = icmp slt i64 %ca, %cb
+  %select1 = select i1 %cmp1, i32 %a, i32 7
+  ret i32 %select1
+}
+
+define i32 @fcmp-iselect(float %ca, float %cb, i32 %a, i32 %b) {
+; SFB64-LABEL: 'fcmp-iselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt float %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select i1 %fcmp1, i32 %a, i32 %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 %select1
+;
+; RV64-LABEL: 'fcmp-iselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt float %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select i1 %fcmp1, i32 %a, i32 %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 %select1
+;
+  %fcmp1 = fcmp ogt float %ca, %cb
+  %select1 = select i1 %fcmp1, i32 %a, i32 %b
+  ret i32 %select1
+}
+
+define float @fcmp-fselect(float %ca, float %cb, float %a, float %b) {
+; SFB64-LABEL: 'fcmp-fselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt float %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fselect1 = select i1 %fcmp1, float %a, float %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %fselect1
+;
+; RV64-LABEL: 'fcmp-fselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt float %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fselect1 = select i1 %fcmp1, float %a, float %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %fselect1
+;
+  %fcmp1 = fcmp ogt float %ca, %cb
+  %fselect1 = select i1 %fcmp1, float %a, float %b
+  ret float %fselect1
+}
+
+define float @icmp-fselect(i64 %ca, i64 %cb, float %a, float %b) {
+; SFB64-LABEL: 'icmp-fselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %icmp1 = icmp slt i64 %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fselect1 = select i1 %icmp1, float %a, float %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %fselect1
+;
+; RV64-LABEL: 'icmp-fselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %icmp1 = icmp slt i64 %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fselect1 = select i1 %icmp1, float %a, float %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret float %fselect1
+;
+  %icmp1 = icmp slt i64 %ca, %cb
+  %fselect1 = select i1 %icmp1, float %a, float %b
+  ret float %fselect1
+}
+
+define <2 x i32> @vector-icmp-vector-iselect(<2 x i32> %ca, <2 x i32> %cb, <2 x i32> %a, <2 x i32> %b) {
+; SFB64-LABEL: 'vector-icmp-vector-iselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %icmp = icmp slt <2 x i32> %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select <2 x i1> %icmp, <2 x i32> %a, <2 x i32> %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x i32> %select1
+;
+; RV64-LABEL: 'vector-icmp-vector-iselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %icmp = icmp slt <2 x i32> %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select <2 x i1> %icmp, <2 x i32> %a, <2 x i32> %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x i32> %select1
+;
+  %icmp = icmp slt <2 x i32> %ca, %cb
+  %select1 = select <2 x i1> %icmp, <2 x i32> %a, <2 x i32> %b
+  ret <2 x i32> %select1
+}
+
+define <2 x i32> @vector-fcmp-vector-iselect(<2 x float> %ca, <2 x float> %cb, <2 x i32> %a, <2 x i32> %b) {
+; SFB64-LABEL: 'vector-fcmp-vector-iselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt <2 x float> %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select <2 x i1> %fcmp1, <2 x i32> %a, <2 x i32> %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x i32> %select1
+;
+; RV64-LABEL: 'vector-fcmp-vector-iselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt <2 x float> %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select <2 x i1> %fcmp1, <2 x i32> %a, <2 x i32> %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x i32> %select1
+;
+  %fcmp1 = fcmp ogt <2 x float> %ca, %cb
+  %select1 = select <2 x i1> %fcmp1, <2 x i32> %a, <2 x i32> %b
+  ret <2 x i32> %select1
+}
+
+define <2 x float> @vector-fcmp-vector-fselect(<2 x float> %ca, <2 x float> %cb, <2 x float> %a, <2 x float> %b) {
+; SFB64-LABEL: 'vector-fcmp-vector-fselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt <2 x float> %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select <2 x i1> %fcmp1, <2 x float> %a, <2 x float> %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x float> %select1
+;
+; RV64-LABEL: 'vector-fcmp-vector-fselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt <2 x float> %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select <2 x i1> %fcmp1, <2 x float> %a, <2 x float> %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x float> %select1
+;
+  %fcmp1 = fcmp ogt <2 x float> %ca, %cb
+  %select1 = select <2 x i1> %fcmp1, <2 x float> %a, <2 x float> %b
+  ret <2 x float> %select1
+}
+
+define <2 x float> @vector-icmp-vector-fselect(<2 x i32> %ca, <2 x i32> %cb, <2 x float> %a, <2 x float> %b) {
+; SFB64-LABEL: 'vector-icmp-vector-fselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %icmp1 = icmp slt <2 x i32> %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select <2 x i1> %icmp1, <2 x float> %a, <2 x float> %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x float> %select1
+;
+; RV64-LABEL: 'vector-icmp-vector-fselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %icmp1 = icmp slt <2 x i32> %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %select1 = select <2 x i1> %icmp1, <2 x float> %a, <2 x float> %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x float> %select1
+;
+  %icmp1 = icmp slt <2 x i32> %ca, %cb
+  %select1 = select <2 x i1> %icmp1, <2 x float> %a, <2 x float> %b
+  ret <2 x float> %select1
+}
+
+define <2 x float> @icmp-vector-fselect(i1 %ca, i1 %cb, <2 x float> %a, <2 x float> %b) {
+; SFB64-LABEL: 'icmp-vector-fselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %icmp1 = icmp slt i1 %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %select1 = select i1 %icmp1, <2 x float> %a, <2 x float> %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x float> %select1
+;
+; RV64-LABEL: 'icmp-vector-fselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %icmp1 = icmp slt i1 %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %select1 = select i1 %icmp1, <2 x float> %a, <2 x float> %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x float> %select1
+;
+  %icmp1 = icmp slt i1 %ca, %cb
+  %select1 = select i1 %icmp1, <2 x float> %a, <2 x float> %b
+  ret <2 x float> %select1
+}
+
+define <2 x i32> @icmp-vector-iselect(i1 %ca, i1 %cb, <2 x i32> %a, <2 x i32> %b) {
+; SFB64-LABEL: 'icmp-vector-iselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %icmp1 = icmp slt i1 %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %select1 = select i1 %icmp1, <2 x i32> %a, <2 x i32> %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x i32> %select1
+;
+; RV64-LABEL: 'icmp-vector-iselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %icmp1 = icmp slt i1 %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %select1 = select i1 %icmp1, <2 x i32> %a, <2 x i32> %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x i32> %select1
+;
+  %icmp1 = icmp slt i1 %ca, %cb
+  %select1 = select i1 %icmp1, <2 x i32> %a, <2 x i32> %b
+  ret <2 x i32> %select1
+}
+
+define <2 x float> @fcmp-vector-fselect(float %ca, float %cb, <2 x float> %a, <2 x float> %b) {
+; SFB64-LABEL: 'fcmp-vector-fselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt float %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %select1 = select i1 %fcmp1, <2 x float> %a, <2 x float> %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x float> %select1
+;
+; RV64-LABEL: 'fcmp-vector-fselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt float %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %select1 = select i1 %fcmp1, <2 x float> %a, <2 x float> %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x float> %select1
+;
+  %fcmp1 = fcmp ogt float %ca, %cb
+  %select1 = select i1 %fcmp1, <2 x float> %a, <2 x float> %b
+  ret <2 x float> %select1
+}
+
+define <2 x i32> @fcmp-vector-iselect(float %ca, float %cb, <2 x i32> %a, <2 x i32> %b) {
+; SFB64-LABEL: 'fcmp-vector-iselect'
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt float %ca, %cb
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %select1 = select i1 %fcmp1, <2 x i32> %a, <2 x i32> %b
+; SFB64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x i32> %select1
+;
+; RV64-LABEL: 'fcmp-vector-iselect'
+; RV64-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %fcmp1 = fcmp ogt float %ca, %cb
+; RV64-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %select1 = select i1 %fcmp1, <2 x i32> %a, <2 x i32> %b
+; RV64-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x i32> %select1
+;
+  %fcmp1 = fcmp ogt float %ca, %cb
+  %select1 = select i1 %fcmp1, <2 x i32> %a, <2 x i32> %b
+  ret <2 x i32> %select1
+}