Revert r301950: SpeculativeExecution: Stop using whitelist for costs

This pass doesn't correctly handle testing for when it is legal to hoist
arbitrary instructions. The whitelist happens to make it safe, so before
it is removed the pass's legality checks will need to be enhanced.

Details have been added to the code review thread for the patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302640 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/SpeculativeExecution.cpp b/lib/Transforms/Scalar/SpeculativeExecution.cpp
index a0fc966cee2c6a673d13bcf166c9ff6313131c21..a7c308b598779bea435424d871a148e2c3b3443e 100644 (file)
--- a/lib/Transforms/Scalar/SpeculativeExecution.cpp
+++ b/lib/Transforms/Scalar/SpeculativeExecution.cpp
@@ -208,6 +208,47 @@ bool SpeculativeExecutionPass::runOnBasicBlock(BasicBlock &B) {
   return false;
 }
 
+static unsigned ComputeSpeculationCost(const Instruction *I,
+                                       const TargetTransformInfo &TTI) {
+  switch (Operator::getOpcode(I)) {
+    case Instruction::GetElementPtr:
+    case Instruction::Add:
+    case Instruction::Mul:
+    case Instruction::And:
+    case Instruction::Or:
+    case Instruction::Select:
+    case Instruction::Shl:
+    case Instruction::Sub:
+    case Instruction::LShr:
+    case Instruction::AShr:
+    case Instruction::Xor:
+    case Instruction::ZExt:
+    case Instruction::SExt:
+    case Instruction::Call:
+    case Instruction::BitCast:
+    case Instruction::PtrToInt:
+    case Instruction::IntToPtr:
+    case Instruction::AddrSpaceCast:
+    case Instruction::FPToUI:
+    case Instruction::FPToSI:
+    case Instruction::UIToFP:
+    case Instruction::SIToFP:
+    case Instruction::FPExt:
+    case Instruction::FPTrunc:
+    case Instruction::FAdd:
+    case Instruction::FSub:
+    case Instruction::FMul:
+    case Instruction::FDiv:
+    case Instruction::FRem:
+    case Instruction::ICmp:
+    case Instruction::FCmp:
+      return TTI.getUserCost(I);
+
+    default:
+      return UINT_MAX; // Disallow anything not whitelisted.
+  }
+}
+
 bool SpeculativeExecutionPass::considerHoistingFromTo(
     BasicBlock &FromBlock, BasicBlock &ToBlock) {
   SmallSet<const Instruction *, 8> NotHoisted;
@@ -223,7 +264,7 @@ bool SpeculativeExecutionPass::considerHoistingFromTo(
 
   unsigned TotalSpeculationCost = 0;
   for (auto& I : FromBlock) {
-    const unsigned Cost = TTI->getUserCost(&I);
+    const unsigned Cost = ComputeSpeculationCost(&I, *TTI);
     if (Cost != UINT_MAX && isSafeToSpeculativelyExecute(&I) &&
         AllPrecedingUsesFromBlockHoisted(&I)) {
       TotalSpeculationCost += Cost;

diff --git a/test/Transforms/SpeculativeExecution/spec-other.ll b/test/Transforms/SpeculativeExecution/spec-other.ll
deleted file mode 100644 (file)
index 65e14b6..0000000
--- a/test/Transforms/SpeculativeExecution/spec-other.ll
+++ /dev/null
@@ -1,32 +0,0 @@
-; RUN: opt < %s -S -speculative-execution \
-; RUN:   -spec-exec-max-speculation-cost 4 -spec-exec-max-not-hoisted 3 \
-; RUN:   | FileCheck %s
-
-; CHECK-LABEL: @ifThen_extractvalue(
-; CHECK: extractvalue
-; CHECK: br i1 true
-define void @ifThen_extractvalue() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = extractvalue { i32, i32 } undef, 0
-  br label %b
-
-b:
-  ret void
-}
-
-; CHECK-LABEL: @ifThen_insertvalue(
-; CHECK: insertvalue
-; CHECK: br i1 true
-define void @ifThen_insertvalue() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = insertvalue { i32, i32 } undef, i32 undef, 0
-  br label %b
-
-b:
-  ret void
-}
-

diff --git a/test/Transforms/SpeculativeExecution/spec-vector.ll b/test/Transforms/SpeculativeExecution/spec-vector.ll
deleted file mode 100644 (file)
index 9c64f1f..0000000
--- a/test/Transforms/SpeculativeExecution/spec-vector.ll
+++ /dev/null
@@ -1,73 +0,0 @@
-; RUN: opt < %s -S -speculative-execution \
-; RUN:   -spec-exec-max-speculation-cost 4 -spec-exec-max-not-hoisted 3 \
-; RUN:   | FileCheck %s
-
-; CHECK-LABEL: @ifThen_extractelement_constindex(
-; CHECK: extractelement
-; CHECK: br i1 true
-define void @ifThen_extractelement_constindex() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = extractelement <4 x i32> undef, i32 0
-  br label %b
-
-b:
-  ret void
-}
-
-; CHECK-LABEL: @ifThen_extractelement_varindex(
-; CHECK: extractelement
-; CHECK: br i1 true
-define void @ifThen_extractelement_varindex(i32 %idx) {
-  br i1 true, label %a, label %b
-
-a:
-  %x = extractelement <4 x i32> undef, i32 %idx
-  br label %b
-
-b:
-  ret void
-}
-
-; CHECK-LABEL: @ifThen_insertelement_constindex(
-; CHECK: insertelement
-; CHECK: br i1 true
-define void @ifThen_insertelement_constindex() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = insertelement <4 x i32> undef, i32 undef, i32 0
-  br label %b
-
-b:
-  ret void
-}
-
-; CHECK-LABEL: @ifThen_insertelement_varindex(
-; CHECK: insertelement
-; CHECK: br i1 true
-define void @ifThen_insertelement_varindex(i32 %idx) {
-  br i1 true, label %a, label %b
-
-a:
-  %x = insertelement <4 x i32> undef, i32 undef, i32 %idx
-  br label %b
-
-b:
-  ret void
-}
-
-; CHECK-LABEL: @ifThen_shufflevector(
-; CHECK: shufflevector
-; CHECK: br i1 true
-define void @ifThen_shufflevector() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = shufflevector <4 x i32> undef, <4 x i32> undef, <4 x i32> undef
-  br label %b
-
-b:
-  ret void
-}