SpeculativeExecution: Allow speculating more instruction types

[piotr]

Summary

Support more instructions in SpeculativeExecution pass:

• ExtractValue
• InsertValue
• Trunc
• Freeze

[piotr]

As Matt pointed out in D91633, extractvalue and insertvalue were also missing, so I am adding them here (the new tests are taken from D24543). Also the tests added earlier in D91633 are being moved to spec-other.ll.

[piotr]

Added two more instructions: trunc and freeze (thanks @foad).

[foad]

In D91688#2402592, @piotr wrote:

Added two more instructions: trunc and freeze (thanks @foad).

Thanks! Stepping back a bit, why does this pass have a whitelist of instructions at all, instead of just relying on isSafeToSpeculativelyExecute?

[piotr]

I asked myself the same question - this was tried before - see https://reviews.llvm.org/D24544. I do not know any more details.

llvm/lib/Transforms/Scalar/SpeculativeExecution.cpp

switch (Operator::getOpcode(I)) {
     case Instruction::FAdd:
     case Instruction::FSub:
     case Instruction::FMul:
     case Instruction::FDiv:
     case Instruction::FRem:
     case Instruction::FNeg:
     case Instruction::ICmp:
     case Instruction::FCmp:
+    case Instruction::Trunc:
+    case Instruction::Freeze:
     case Instruction::ExtractElement:
     case Instruction::InsertElement:
     case Instruction::ShuffleVector:
+    case Instruction::ExtractValue:
+    case Instruction::InsertValue:
       return TTI.getUserCost(I, TargetTransformInfo::TCK_SizeAndLatency);
 
     default:
       return UINT_MAX; // Disallow anything not explicitly listed.
   }
 }
 
 bool SpeculativeExecutionPass::considerHoistingFromTo(

llvm/test/Transforms/SpeculativeExecution/spec-casts.ll

define void @ifThen_fptrunc() {
   br i1 true, label %a, label %b
 a:
   %x = fptrunc double undef to float
   br label %b
 
 b:
   ret void
 }
+
+; CHECK-LABEL: @ifThen_trunc(
+; CHECK: trunc
+; CHECK: br i1 true
+define void @ifThen_trunc() {
+  br i1 true, label %a, label %b
+a:
+  %x = trunc i32 undef to i16
+  br label %b
+
+b:
+  ret void
+}

llvm/test/Transforms/SpeculativeExecution/spec-fp.ll

 
 a:
   %x = frem float undef, undef
   br label %b
 
 b:
   ret void
 }
-
-; CHECK-LABEL: @ifThen_shuffle(
-; CHECK: shufflevector
-; CHECK: br i1 true
-define void @ifThen_shuffle() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = shufflevector <2 x float> undef, <2 x float> undef, <2 x i32> zeroinitializer
-  br label %b
-
-b:
-  ret void
-}
-
-; CHECK-LABEL: @ifThen_extract(
-; CHECK: extractelement
-; CHECK: br i1 true
-define void @ifThen_extract() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = extractelement <2 x float> undef, i32 1
-  br label %b
-
-b:
-  ret void
-}
-
-
-; CHECK-LABEL: @ifThen_insert(
-; CHECK: insertelement
-; CHECK: br i1 true
-define void @ifThen_insert() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = insertelement <2 x float> undef, float undef, i32 1
-  br label %b
-
-b:
-  ret void
-}

llvm/test/Transforms/SpeculativeExecution/spec-other.ll

 ; 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_fadd(
-; CHECK: fadd
-; CHECK: br i1 true
-define void @ifThen_fadd() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = fadd float undef, undef
-  br label %b
-
-b:
-  ret void
-}
-
-; CHECK-LABEL: @ifThen_fsub(
-; CHECK: fsub
-; CHECK: br i1 true
-define void @ifThen_fsub() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = fsub float undef, undef
-  br label %b
-
-b:
-  ret void
-}
-
-; CHECK-LABEL: @ifThen_binary_fneg(
-; CHECK: fsub float -0.0
-; CHECK: br i1 true
-define void @ifThen_binary_fneg() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = fsub float -0.0, undef
-  br label %b
-
-b:
-  ret void
-}
-
-; CHECK-LABEL: @ifThen_unary_fneg(
-; CHECK: fneg float
+; CHECK-LABEL: @ifThen_shuffle(
+; CHECK: shufflevector
 ; CHECK: br i1 true
-define void @ifThen_unary_fneg() {
+define void @ifThen_shuffle() {
   br i1 true, label %a, label %b
 
 a:
-  %x = fneg float undef
+  %x = shufflevector <2 x float> undef, <2 x float> undef, <2 x i32> zeroinitializer
   br label %b
 
 b:
   ret void
 }
 
-; CHECK-LABEL: @ifThen_fmul(
-; CHECK: fmul
+; CHECK-LABEL: @ifThen_extract(
+; CHECK: extractelement
 ; CHECK: br i1 true
-define void @ifThen_fmul() {
+define void @ifThen_extract() {
   br i1 true, label %a, label %b
 
 a:
-  %x = fmul float undef, undef
+  %x = extractelement <2 x float> undef, i32 1
   br label %b
 
 b:
   ret void
 }
 
-; CHECK-LABEL: @ifThen_fdiv(
-; CHECK: fdiv
-; CHECK: br i1 true
-define void @ifThen_fdiv() {
-  br i1 true, label %a, label %b
-
-a:
-  %x = fdiv float undef, undef
-  br label %b
-
-b:
-  ret void
-}
 
-; CHECK-LABEL: @ifThen_frem(
-; CHECK: frem
+; CHECK-LABEL: @ifThen_insert(
+; CHECK: insertelement
 ; CHECK: br i1 true
-define void @ifThen_frem() {
+define void @ifThen_insert() {
   br i1 true, label %a, label %b
 
 a:
-  %x = frem float undef, undef
+  %x = insertelement <2 x float> undef, float undef, i32 1
   br label %b
 
 b:
   ret void
 }
 
-; CHECK-LABEL: @ifThen_shuffle(
-; CHECK: shufflevector
+; CHECK-LABEL: @ifThen_extractvalue(
+; CHECK: extractvalue
 ; CHECK: br i1 true
-define void @ifThen_shuffle() {
+define void @ifThen_extractvalue() {
   br i1 true, label %a, label %b
 
 a:
-  %x = shufflevector <2 x float> undef, <2 x float> undef, <2 x i32> zeroinitializer
+  %x = extractvalue { i32, i32 } undef, 0
   br label %b
 
 b:
   ret void
 }
 
-; CHECK-LABEL: @ifThen_extract(
-; CHECK: extractelement
+; CHECK-LABEL: @ifThen_insertvalue(
+; CHECK: insertvalue
 ; CHECK: br i1 true
-define void @ifThen_extract() {
+define void @ifThen_insertvalue() {
   br i1 true, label %a, label %b
 
 a:
-  %x = extractelement <2 x float> undef, i32 1
+  %x = insertvalue { i32, i32 } undef, i32 undef, 0
   br label %b
 
 b:
   ret void
 }
 
-
-; CHECK-LABEL: @ifThen_insert(
-; CHECK: insertelement
+; CHECK-LABEL: @ifThen_freeze(
+; CHECK: freeze
 ; CHECK: br i1 true
-define void @ifThen_insert() {
+define void @ifThen_freeze() {
   br i1 true, label %a, label %b
 
 a:
-  %x = insertelement <2 x float> undef, float undef, i32 1
+  %x = freeze i32 undef
   br label %b
 
 b:
   ret void
 }