maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[ValueTracking] Let isGuaranteedNotToBeUndefOrPoison consider noundef 

This patch adds support for noundef arguments.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D83752
This commit is contained in:
Juneyoung Lee 2020-07-17 12:53:08 +09:00
parent cd4953246b
commit 582901d0b5
2 changed files with 13 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
llvm/lib/Analysis/ValueTracking.cpp
View File

@ -4766,6 +4766,12 @@ bool llvm::isGuaranteedNotToBeUndefOrPoison(const Value *V,
// TODO: Some instructions are guaranteed to return neither undef
// nor poison if their arguments are not poison/undef.
if (auto *A = dyn_cast<Argument>(V)) {
// NoUndef does not guarantee that paddings are not undef.
if (A->hasAttribute(Attribute::NoUndef))
return true;
}
if (auto *C = dyn_cast<Constant>(V)) {
// TODO: We can analyze ConstExpr by opcode to determine if there is any
// possibility of poison.

13
llvm/test/Transforms/InstSimplify/freeze-noundef.ll
View File

@ -3,8 +3,7 @@
define i8 @noundef(i8 noundef %x) {
; CHECK-LABEL: @noundef(
; CHECK-NEXT: [[Y:%.*]] = freeze i8 [[X:%.*]]
; CHECK-NEXT: ret i8 [[Y]]
; CHECK-NEXT: ret i8 [[X:%.*]]
;
%y = freeze i8 %x
ret i8 %y
@ -13,14 +12,14 @@ define i8 @noundef(i8 noundef %x) {
define i1 @icmp(i8 noundef %x, i8 noundef %y) {
; CHECK-LABEL: @icmp(
; CHECK-NEXT: [[C:%.*]] = icmp eq i8 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[F:%.*]] = freeze i1 [[C]]
; CHECK-NEXT: ret i1 [[F]]
; CHECK-NEXT: ret i1 [[C]]
;
%c = icmp eq i8 %x, %y
%f = freeze i1 %c
ret i1 %f
}
; TODO: should look into binary operations
define i1 @or(i1 noundef %x, i1 noundef %x2) {
; CHECK-LABEL: @or(
; CHECK-NEXT: [[Y:%.*]] = or i1 [[X:%.*]], [[X2:%.*]]
@ -43,6 +42,7 @@ define i1 @or2(i1 noundef %x, i1 %x2) {
ret i1 %z
}
; TODO: should look into binary operations
define i8 @add(i8 noundef %x) {
; CHECK-LABEL: @add(
; CHECK-NEXT: [[Y:%.*]] = add i8 [[X:%.*]], 1
@ -67,13 +67,13 @@ define i8 @addnsw(i8 noundef %x) {
define {i8, i32} @aggr({i8, i32} noundef %x) {
; CHECK-LABEL: @aggr(
; CHECK-NEXT: [[Y:%.*]] = freeze { i8, i32 } [[X:%.*]]
; CHECK-NEXT: ret { i8, i32 } [[Y]]
; CHECK-NEXT: ret { i8, i32 } [[X:%.*]]
;
%y = freeze {i8, i32} %x
ret {i8, i32} %y
}
; TODO: should look into extract operations
define i32 @extract({i8, i32} noundef %x) {
; CHECK-LABEL: @extract(
; CHECK-NEXT: [[Y:%.*]] = extractvalue { i8, i32 } [[X:%.*]], 1
@ -85,6 +85,7 @@ define i32 @extract({i8, i32} noundef %x) {
ret i32 %z
}
; TODO: should look into extract operations
define i32 @extract2({i8, {i8, i32}} noundef %x) {
; CHECK-LABEL: @extract2(
; CHECK-NEXT: [[Y:%.*]] = extractvalue { i8, { i8, i32 } } [[X:%.*]], 1