[llvm] r331889 - [InstCombine] snprintf optimizations
David Bolvansky via llvm-commits
llvm-commits at lists.llvm.org
Wed May 9 09:09:31 PDT 2018
Author: xbolva00
Date: Wed May 9 09:09:31 2018
New Revision: 331889
URL: http://llvm.org/viewvc/llvm-project?rev=331889&view=rev
Log:
[InstCombine] snprintf optimizations
Reviewers: spatel, efriedma, majnemer, rja, bkramer
Reviewed By: rja, bkramer
Subscribers: rja, llvm-commits
Differential Revision: https://reviews.llvm.org/D46285
Added:
llvm/trunk/test/Transforms/InstCombine/snprintf.ll
Modified:
llvm/trunk/include/llvm/Transforms/Utils/SimplifyLibCalls.h
llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
Modified: llvm/trunk/include/llvm/Transforms/Utils/SimplifyLibCalls.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/SimplifyLibCalls.h?rev=331889&r1=331888&r2=331889&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/SimplifyLibCalls.h (original)
+++ llvm/trunk/include/llvm/Transforms/Utils/SimplifyLibCalls.h Wed May 9 09:09:31 2018
@@ -159,6 +159,7 @@ private:
int StreamArg = -1);
Value *optimizePrintF(CallInst *CI, IRBuilder<> &B);
Value *optimizeSPrintF(CallInst *CI, IRBuilder<> &B);
+ Value *optimizeSnPrintF(CallInst *CI, IRBuilder<> &B);
Value *optimizeFPrintF(CallInst *CI, IRBuilder<> &B);
Value *optimizeFWrite(CallInst *CI, IRBuilder<> &B);
Value *optimizeFPuts(CallInst *CI, IRBuilder<> &B);
@@ -172,6 +173,7 @@ private:
SmallVectorImpl<CallInst *> &SinCosCalls);
Value *optimizePrintFString(CallInst *CI, IRBuilder<> &B);
Value *optimizeSPrintFString(CallInst *CI, IRBuilder<> &B);
+ Value *optimizeSnPrintFString(CallInst *CI, IRBuilder<> &B);
Value *optimizeFPrintFString(CallInst *CI, IRBuilder<> &B);
/// hasFloatVersion - Checks if there is a float version of the specified
Modified: llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp?rev=331889&r1=331888&r2=331889&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp Wed May 9 09:09:31 2018
@@ -1912,6 +1912,94 @@ Value *LibCallSimplifier::optimizeSPrint
return nullptr;
}
+Value *LibCallSimplifier::optimizeSnPrintFString(CallInst *CI, IRBuilder<> &B) {
+ // Check for a fixed format string.
+ StringRef FormatStr;
+ if (!getConstantStringInfo(CI->getArgOperand(2), FormatStr))
+ return nullptr;
+
+ // Check for size
+ ConstantInt *Size = dyn_cast<ConstantInt>(CI->getArgOperand(1));
+ if (!Size)
+ return nullptr;
+
+ uint64_t N = Size->getZExtValue();
+
+ // If we just have a format string (nothing else crazy) transform it.
+ if (CI->getNumArgOperands() == 3) {
+ // Make sure there's no % in the constant array. We could try to handle
+ // %% -> % in the future if we cared.
+ for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
+ if (FormatStr[i] == '%')
+ return nullptr; // we found a format specifier, bail out.
+
+ if (N == 0)
+ return ConstantInt::get(CI->getType(), FormatStr.size());
+ else if (N < FormatStr.size() + 1)
+ return nullptr;
+
+ // sprintf(str, size, fmt) -> llvm.memcpy(align 1 str, align 1 fmt,
+ // strlen(fmt)+1)
+ B.CreateMemCpy(
+ CI->getArgOperand(0), 1, CI->getArgOperand(2), 1,
+ ConstantInt::get(DL.getIntPtrType(CI->getContext()),
+ FormatStr.size() + 1)); // Copy the null byte.
+ return ConstantInt::get(CI->getType(), FormatStr.size());
+ }
+
+ // The remaining optimizations require the format string to be "%s" or "%c"
+ // and have an extra operand.
+ if (FormatStr.size() == 2 && FormatStr[0] == '%' &&
+ CI->getNumArgOperands() == 4) {
+
+ // Decode the second character of the format string.
+ if (FormatStr[1] == 'c') {
+ if (N == 0)
+ return ConstantInt::get(CI->getType(), 1);
+ else if (N == 1)
+ return nullptr;
+
+ // snprintf(dst, size, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0
+ if (!CI->getArgOperand(3)->getType()->isIntegerTy())
+ return nullptr;
+ Value *V = B.CreateTrunc(CI->getArgOperand(3), B.getInt8Ty(), "char");
+ Value *Ptr = castToCStr(CI->getArgOperand(0), B);
+ B.CreateStore(V, Ptr);
+ Ptr = B.CreateGEP(B.getInt8Ty(), Ptr, B.getInt32(1), "nul");
+ B.CreateStore(B.getInt8(0), Ptr);
+
+ return ConstantInt::get(CI->getType(), 1);
+ }
+
+ if (FormatStr[1] == 's') {
+ // snprintf(dest, size, "%s", str) to llvm.memcpy(dest, str, len+1, 1)
+ StringRef Str;
+ if (!getConstantStringInfo(CI->getArgOperand(3), Str))
+ return nullptr;
+
+ if (N == 0)
+ return ConstantInt::get(CI->getType(), Str.size());
+ else if (N < Str.size() + 1)
+ return nullptr;
+
+ B.CreateMemCpy(CI->getArgOperand(0), 1, CI->getArgOperand(3), 1,
+ ConstantInt::get(CI->getType(), Str.size() + 1));
+
+ // The snprintf result is the unincremented number of bytes in the string.
+ return ConstantInt::get(CI->getType(), Str.size());
+ }
+ }
+ return nullptr;
+}
+
+Value *LibCallSimplifier::optimizeSnPrintF(CallInst *CI, IRBuilder<> &B) {
+ if (Value *V = optimizeSnPrintFString(CI, B)) {
+ return V;
+ }
+
+ return nullptr;
+}
+
Value *LibCallSimplifier::optimizeFPrintFString(CallInst *CI, IRBuilder<> &B) {
optimizeErrorReporting(CI, B, 0);
@@ -2318,6 +2406,8 @@ Value *LibCallSimplifier::optimizeCall(C
return optimizePrintF(CI, Builder);
case LibFunc_sprintf:
return optimizeSPrintF(CI, Builder);
+ case LibFunc_snprintf:
+ return optimizeSnPrintF(CI, Builder);
case LibFunc_fprintf:
return optimizeFPrintF(CI, Builder);
case LibFunc_fwrite:
Added: llvm/trunk/test/Transforms/InstCombine/snprintf.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/snprintf.ll?rev=331889&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/snprintf.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/snprintf.ll Wed May 9 09:09:31 2018
@@ -0,0 +1,138 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+ at .str = private unnamed_addr constant [4 x i8] c"str\00", align 1
+ at .str.1 = private unnamed_addr constant [3 x i8] c"%%\00", align 1
+ at .str.2 = private unnamed_addr constant [3 x i8] c"%c\00", align 1
+ at .str.3 = private unnamed_addr constant [3 x i8] c"%s\00", align 1
+
+declare i32 @snprintf(i8*, i64, i8*, ...) #1
+
+define void @test_not_const_fmt(i8* %buf, i8* %fmt) #0 {
+; CHECK-LABEL: @test_not_const_fmt(
+; CHECK-NEXT: [[CALL:%.*]] = call i32 (i8*, i64, i8*, ...) @snprintf(i8* [[BUF:%.*]], i64 32, i8* [[FMT:%.*]])
+; CHECK-NEXT: ret void
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 32, i8* %fmt) #2
+ ret void
+}
+
+define void @test_not_const_fmt_zero_size_return_value(i8* %buf, i8* %fmt) #0 {
+; CHECK-LABEL: @test_not_const_fmt_zero_size_return_value(
+; CHECK-NEXT: [[CALL:%.*]] = call i32 (i8*, i64, i8*, ...) @snprintf(i8* [[BUF:%.*]], i64 0, i8* [[FMT:%.*]])
+; CHECK-NEXT: ret void
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 0, i8* %fmt) #2
+ ret void
+}
+
+
+define void @test_not_const_size(i8* %buf, i64 %size) #0 {
+; CHECK-LABEL: @test_not_const_size(
+; CHECK-NEXT: [[CALL:%.*]] = call i32 (i8*, i64, i8*, ...) @snprintf(i8* [[BUF:%.*]], i64 [[SIZE:%.*]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0))
+; CHECK-NEXT: ret void
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 %size, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0)) #2
+ ret void
+}
+
+
+define i32 @test_return_value(i8* %buf) #0 {
+; CHECK-LABEL: @test_return_value(
+; CHECK-NEXT: ret i32 3
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 0, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0)) #2
+ ret i32 %call
+}
+
+define void @test_percentage(i8* %buf) #0 {
+; CHECK-LABEL: @test_percentage(
+; CHECK-NEXT: [[CALL:%.*]] = call i32 (i8*, i64, i8*, ...) @snprintf(i8* [[BUF:%.*]], i64 32, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0))
+; CHECK-NEXT: ret void
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 32, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0)) #2
+ ret void
+}
+
+define i32 @test_null_buf_return_value() #0 {
+; CHECK-LABEL: @test_null_buf_return_value(
+; CHECK-NEXT: ret i32 3
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* null, i64 0, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0)) #2
+ ret i32 %call
+}
+
+define i32 @test_percentage_return_value() #0 {
+; CHECK-LABEL: @test_percentage_return_value(
+; CHECK-NEXT: [[CALL:%.*]] = call i32 (i8*, i64, i8*, ...) @snprintf(i8* null, i64 0, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0))
+; CHECK-NEXT: ret i32 [[CALL]]
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* null, i64 0, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.1, i64 0, i64 0)) #3
+ ret i32 %call
+}
+
+
+define void @test_correct_copy(i8* %buf) #0 {
+; CHECK-LABEL: @test_correct_copy(
+; CHECK-NEXT: [[TMP1:%.*]] = bitcast i8* [[BUF:%.*]] to i32*
+; CHECK-NEXT: store i32 7500915, i32* [[TMP1]], align 1
+; CHECK-NEXT: ret void
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 32, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0)) #2
+ ret void
+}
+
+define i32 @test_char_zero_size(i8* %buf) #0 {
+; CHECK-LABEL: @test_char_zero_size(
+; CHECK-NEXT: ret i32 1
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 0, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i32 65) #2
+ ret i32 %call
+}
+
+define i32 @test_char_wrong_size(i8* %buf) #0 {
+; CHECK-LABEL: @test_char_wrong_size(
+; CHECK-NEXT: [[CALL:%.*]] = call i32 (i8*, i64, i8*, ...) @snprintf(i8* [[BUF:%.*]], i64 1, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i32 65)
+; CHECK-NEXT: ret i32 [[CALL]]
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 1, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i32 65) #2
+ ret i32 %call
+}
+
+define i32 @test_char_ok_size(i8* %buf) #0 {
+; CHECK-LABEL: @test_char_ok_size(
+; CHECK-NEXT: store i8 65, i8* [[BUF:%.*]], align 1
+; CHECK-NEXT: [[NUL:%.*]] = getelementptr i8, i8* [[BUF]], i64 1
+; CHECK-NEXT: store i8 0, i8* [[NUL]], align 1
+; CHECK-NEXT: ret i32 1
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 32, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i32 65) #2
+ ret i32 %call
+}
+
+define i32 @test_str_zero_size(i8* %buf) #0 {
+; CHECK-LABEL: @test_str_zero_size(
+; CHECK-NEXT: ret i32 3
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 0, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.3, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0)) #2
+ ret i32 %call
+}
+
+define i32 @test_str_wrong_size(i8* %buf) #0 {
+; CHECK-LABEL: @test_str_wrong_size(
+; CHECK-NEXT: [[CALL:%.*]] = call i32 (i8*, i64, i8*, ...) @snprintf(i8* [[BUF:%.*]], i64 1, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.3, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0))
+; CHECK-NEXT: ret i32 [[CALL]]
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 1, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.3, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0)) #2
+ ret i32 %call
+}
+
+define i32 @test_str_ok_size(i8* %buf) #0 {
+; CHECK-LABEL: @test_str_ok_size(
+; CHECK-NEXT: [[TMP1:%.*]] = bitcast i8* [[BUF:%.*]] to i32*
+; CHECK-NEXT: store i32 7500915, i32* [[TMP1]], align 1
+; CHECK-NEXT: ret i32 3
+;
+ %call = call i32 (i8*, i64, i8*, ...) @snprintf(i8* %buf, i64 32, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.3, i64 0, i64 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0)) #2
+ ret i32 %call
+}
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