[PATCH] D100724: [SimplifyLibCalls] Transform printf("%s", str) --> puts(str)/noop.
Dawid Jurczak via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 23 08:04:57 PDT 2021
yurai007 updated this revision to Diff 340038.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D100724/new/
https://reviews.llvm.org/D100724
Files:
llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
llvm/test/Transforms/InstCombine/printf-2.ll
Index: llvm/test/Transforms/InstCombine/printf-2.ll
===================================================================
--- llvm/test/Transforms/InstCombine/printf-2.ll
+++ llvm/test/Transforms/InstCombine/printf-2.ll
@@ -24,6 +24,8 @@
; CHECK: @[[CHARSTR:[a-zA-Z0-9_$"\\.-]+]] = constant [2 x i8] c"a\00"
; CHECK: @[[EMPTY:[a-zA-Z0-9_$"\\.-]+]] = constant [1 x i8] zeroinitializer
; CHECK: @[[STR:[a-zA-Z0-9_$"\\.-]+]] = private unnamed_addr constant [12 x i8] c"hello world\00", align 1
+; CHECK: @[[STR_1:[a-zA-Z0-9_$"\\.-]+]] = private unnamed_addr constant [12 x i8] c"hello world\00", align 1
+; CHECK: @[[STR_2:[a-zA-Z0-9_$"\\.-]+]] = private unnamed_addr constant [12 x i8] c"hello world\00", align 1
;.
define void @test_simplify1() {
; CHECK-LABEL: @test_simplify1(
@@ -67,9 +69,10 @@
ret void
}
+; printf("%s", "") --> noop
+
define void @test_simplify8() {
; CHECK-LABEL: @test_simplify8(
-; CHECK-NEXT: call void (i8*, ...) @printf(i8* noundef nonnull dereferenceable(1) getelementptr inbounds ([3 x i8], [3 x i8]* @format_str, i32 0, i32 0), i8* getelementptr inbounds ([1 x i8], [1 x i8]* @empty, i32 0, i32 0))
; CHECK-NEXT: ret void
;
%fmt = getelementptr [3 x i8], [3 x i8]* @format_str, i32 0, i32 0
@@ -78,9 +81,11 @@
ret void
}
+; printf("%s", str"\n") --> puts(str)
+
define void @test_simplify9() {
; CHECK-LABEL: @test_simplify9(
-; CHECK-NEXT: call void (i8*, ...) @printf(i8* noundef nonnull dereferenceable(1) getelementptr inbounds ([3 x i8], [3 x i8]* @format_str, i32 0, i32 0), i8* getelementptr inbounds ([13 x i8], [13 x i8]* @hello_world, i32 0, i32 0))
+; CHECK-NEXT: [[PUTS:%.*]] = call i32 @puts(i8* nonnull dereferenceable(1) getelementptr inbounds ([12 x i8], [12 x i8]* @str.1, i32 0, i32 0))
; CHECK-NEXT: ret void
;
%fmt = getelementptr [3 x i8], [3 x i8]* @format_str, i32 0, i32 0
@@ -89,11 +94,14 @@
ret void
}
+; printf("%s", "", ...) --> noop
+; printf("%s", "a", ...) --> putchar('a')
+; printf("%s", str"\n", ...) --> puts(str)
+
define void @test_simplify10() {
; CHECK-LABEL: @test_simplify10(
-; CHECK-NEXT: call void (i8*, ...) @printf(i8* noundef nonnull dereferenceable(1) getelementptr inbounds ([3 x i8], [3 x i8]* @format_str, i32 0, i32 0), i8* getelementptr inbounds ([1 x i8], [1 x i8]* @empty, i32 0, i32 0), i32 42, double 0x40091EB860000000)
; CHECK-NEXT: [[PUTCHAR:%.*]] = call i32 @putchar(i32 97)
-; CHECK-NEXT: call void (i8*, ...) @printf(i8* noundef nonnull dereferenceable(1) getelementptr inbounds ([3 x i8], [3 x i8]* @format_str, i32 0, i32 0), i8* getelementptr inbounds ([13 x i8], [13 x i8]* @hello_world, i32 0, i32 0), i32 42, double 0x40091EB860000000)
+; CHECK-NEXT: [[PUTS:%.*]] = call i32 @puts(i8* nonnull dereferenceable(1) getelementptr inbounds ([12 x i8], [12 x i8]* @str.2, i32 0, i32 0))
; CHECK-NEXT: ret void
;
%fmt = getelementptr [3 x i8], [3 x i8]* @format_str, i32 0, i32 0
Index: llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -2377,14 +2377,24 @@
if (FormatStr.size() == 1 || FormatStr == "%%")
return emitPutChar(B.getInt32(FormatStr[0]), B, TLI);
- // printf("%s", "a") --> putchar('a')
+ // Try to remove call or emit putchar/puts.
if (FormatStr == "%s" && CI->getNumArgOperands() > 1) {
- StringRef ChrStr;
- if (!getConstantStringInfo(CI->getOperand(1), ChrStr))
+ StringRef OperandStr;
+ if (!getConstantStringInfo(CI->getOperand(1), OperandStr))
return nullptr;
- if (ChrStr.size() != 1)
- return nullptr;
- return emitPutChar(B.getInt32(ChrStr[0]), B, TLI);
+ // printf("%s", "") --> NOP
+ if (OperandStr.empty())
+ return (Value *)CI;
+ // printf("%s", "a") --> putchar('a')
+ if (OperandStr.size() == 1)
+ return emitPutChar(B.getInt32(OperandStr[0]), B, TLI);
+ // printf("%s", str"\n") --> puts(str)
+ if (OperandStr.back() == '\n') {
+ OperandStr = OperandStr.drop_back();
+ Value *GV = B.CreateGlobalString(OperandStr, "str");
+ return emitPutS(GV, B, TLI);
+ }
+ return nullptr;
}
// printf("foo\n") --> puts("foo")
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D100724.340038.patch
Type: text/x-patch
Size: 4280 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20210423/8ea236ec/attachment.bin>
More information about the llvm-commits
mailing list