llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Björn Pettersson (bjope) <details> <summary>Changes</summary> Make sure that the result from the popcnt/ctlz/cttz intrinsics is unsigned casted to int, rather than casted as a signed value, when expanding the __builtin_popcountg/__builtin_ctzg/__builtin_clzg builtins. An example would be unsigned _BitInt(1) x = ...; int y = __builtin_popcountg(x); which previously was incorrectly expanded to %1 = call i1 @<!-- -->llvm.ctpop.i1(i1 %0) %cast = sext i1 %1 to i32 Since the input type is generic for those "g" versions of the builtins the intrinsic call may return a value for which the sign bit is set (that could typically for BitInt of size 1 and 2). So we need to emit a zext rather than a sext to avoid negative results. --- Full diff: https://github.com/llvm/llvm-project/pull/90845.diff 2 Files Affected: - (modified) clang/lib/CodeGen/CGBuiltin.cpp (+3-3) - (modified) clang/test/CodeGen/builtins.c (+10-10) ``````````diff diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp index a370734e00d3e1..fc1dbb87ed1bf2 100644 --- a/clang/lib/CodeGen/CGBuiltin.cpp +++ b/clang/lib/CodeGen/CGBuiltin.cpp @@ -3239,7 +3239,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID, Builder.getInt1(HasFallback || getTarget().isCLZForZeroUndef()); Value *Result = Builder.CreateCall(F, {ArgValue, ZeroUndef}); if (Result->getType() != ResultType) - Result = Builder.CreateIntCast(Result, ResultType, /*isSigned*/true, + Result = Builder.CreateIntCast(Result, ResultType, /*isSigned*/false, "cast"); if (!HasFallback) return RValue::get(Result); @@ -3271,7 +3271,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID, Builder.getInt1(HasFallback || getTarget().isCLZForZeroUndef()); Value *Result = Builder.CreateCall(F, {ArgValue, ZeroUndef}); if (Result->getType() != ResultType) - Result = Builder.CreateIntCast(Result, ResultType, /*isSigned*/true, + Result = Builder.CreateIntCast(Result, ResultType, /*isSigned*/false, "cast"); if (!HasFallback) return RValue::get(Result); @@ -3351,7 +3351,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID, llvm::Type *ResultType = ConvertType(E->getType()); Value *Result = Builder.CreateCall(F, ArgValue); if (Result->getType() != ResultType) - Result = Builder.CreateIntCast(Result, ResultType, /*isSigned*/true, + Result = Builder.CreateIntCast(Result, ResultType, /*isSigned*/false, "cast"); return RValue::get(Result); } diff --git a/clang/test/CodeGen/builtins.c b/clang/test/CodeGen/builtins.c index 407e0857d22311..b41efb59e61dbc 100644 --- a/clang/test/CodeGen/builtins.c +++ b/clang/test/CodeGen/builtins.c @@ -949,12 +949,12 @@ void test_builtin_popcountg(unsigned char uc, unsigned short us, pop = __builtin_popcountg(uc); // CHECK: %1 = load i8, ptr %uc.addr, align 1 // CHECK-NEXT: %2 = call i8 @llvm.ctpop.i8(i8 %1) - // CHECK-NEXT: %cast = sext i8 %2 to i32 + // CHECK-NEXT: %cast = zext i8 %2 to i32 // CHECK-NEXT: store volatile i32 %cast, ptr %pop, align 4 pop = __builtin_popcountg(us); // CHECK-NEXT: %3 = load i16, ptr %us.addr, align 2 // CHECK-NEXT: %4 = call i16 @llvm.ctpop.i16(i16 %3) - // CHECK-NEXT: %cast1 = sext i16 %4 to i32 + // CHECK-NEXT: %cast1 = zext i16 %4 to i32 // CHECK-NEXT: store volatile i32 %cast1, ptr %pop, align 4 pop = __builtin_popcountg(ui); // CHECK-NEXT: %5 = load i32, ptr %ui.addr, align 4 @@ -992,12 +992,12 @@ void test_builtin_clzg(unsigned char uc, unsigned short us, unsigned int ui, lz = __builtin_clzg(uc); // CHECK: %1 = load i8, ptr %uc.addr, align 1 // CHECK-NEXT: %2 = call i8 @llvm.ctlz.i8(i8 %1, i1 true) - // CHECK-NEXT: %cast = sext i8 %2 to i32 + // CHECK-NEXT: %cast = zext i8 %2 to i32 // CHECK-NEXT: store volatile i32 %cast, ptr %lz, align 4 lz = __builtin_clzg(us); // CHECK-NEXT: %3 = load i16, ptr %us.addr, align 2 // CHECK-NEXT: %4 = call i16 @llvm.ctlz.i16(i16 %3, i1 true) - // CHECK-NEXT: %cast1 = sext i16 %4 to i32 + // CHECK-NEXT: %cast1 = zext i16 %4 to i32 // CHECK-NEXT: store volatile i32 %cast1, ptr %lz, align 4 lz = __builtin_clzg(ui); // CHECK-NEXT: %5 = load i32, ptr %ui.addr, align 4 @@ -1026,7 +1026,7 @@ void test_builtin_clzg(unsigned char uc, unsigned short us, unsigned int ui, lz = __builtin_clzg(uc, sc); // CHECK-NEXT: %15 = load i8, ptr %uc.addr, align 1 // CHECK-NEXT: %16 = call i8 @llvm.ctlz.i8(i8 %15, i1 true) - // CHECK-NEXT: %cast6 = sext i8 %16 to i32 + // CHECK-NEXT: %cast6 = zext i8 %16 to i32 // CHECK-NEXT: %iszero = icmp eq i8 %15, 0 // CHECK-NEXT: %17 = load i8, ptr %sc.addr, align 1 // CHECK-NEXT: %conv = sext i8 %17 to i32 @@ -1035,7 +1035,7 @@ void test_builtin_clzg(unsigned char uc, unsigned short us, unsigned int ui, lz = __builtin_clzg(us, uc); // CHECK-NEXT: %18 = load i16, ptr %us.addr, align 2 // CHECK-NEXT: %19 = call i16 @llvm.ctlz.i16(i16 %18, i1 true) - // CHECK-NEXT: %cast7 = sext i16 %19 to i32 + // CHECK-NEXT: %cast7 = zext i16 %19 to i32 // CHECK-NEXT: %iszero8 = icmp eq i16 %18, 0 // CHECK-NEXT: %20 = load i8, ptr %uc.addr, align 1 // CHECK-NEXT: %conv9 = zext i8 %20 to i32 @@ -1094,12 +1094,12 @@ void test_builtin_ctzg(unsigned char uc, unsigned short us, unsigned int ui, tz = __builtin_ctzg(uc); // CHECK: %1 = load i8, ptr %uc.addr, align 1 // CHECK-NEXT: %2 = call i8 @llvm.cttz.i8(i8 %1, i1 true) - // CHECK-NEXT: %cast = sext i8 %2 to i32 + // CHECK-NEXT: %cast = zext i8 %2 to i32 // CHECK-NEXT: store volatile i32 %cast, ptr %tz, align 4 tz = __builtin_ctzg(us); // CHECK-NEXT: %3 = load i16, ptr %us.addr, align 2 // CHECK-NEXT: %4 = call i16 @llvm.cttz.i16(i16 %3, i1 true) - // CHECK-NEXT: %cast1 = sext i16 %4 to i32 + // CHECK-NEXT: %cast1 = zext i16 %4 to i32 // CHECK-NEXT: store volatile i32 %cast1, ptr %tz, align 4 tz = __builtin_ctzg(ui); // CHECK-NEXT: %5 = load i32, ptr %ui.addr, align 4 @@ -1128,7 +1128,7 @@ void test_builtin_ctzg(unsigned char uc, unsigned short us, unsigned int ui, tz = __builtin_ctzg(uc, sc); // CHECK-NEXT: %15 = load i8, ptr %uc.addr, align 1 // CHECK-NEXT: %16 = call i8 @llvm.cttz.i8(i8 %15, i1 true) - // CHECK-NEXT: %cast6 = sext i8 %16 to i32 + // CHECK-NEXT: %cast6 = zext i8 %16 to i32 // CHECK-NEXT: %iszero = icmp eq i8 %15, 0 // CHECK-NEXT: %17 = load i8, ptr %sc.addr, align 1 // CHECK-NEXT: %conv = sext i8 %17 to i32 @@ -1137,7 +1137,7 @@ void test_builtin_ctzg(unsigned char uc, unsigned short us, unsigned int ui, tz = __builtin_ctzg(us, uc); // CHECK-NEXT: %18 = load i16, ptr %us.addr, align 2 // CHECK-NEXT: %19 = call i16 @llvm.cttz.i16(i16 %18, i1 true) - // CHECK-NEXT: %cast7 = sext i16 %19 to i32 + // CHECK-NEXT: %cast7 = zext i16 %19 to i32 // CHECK-NEXT: %iszero8 = icmp eq i16 %18, 0 // CHECK-NEXT: %20 = load i8, ptr %uc.addr, align 1 // CHECK-NEXT: %conv9 = zext i8 %20 to i32 `````````` </details> https://github.com/llvm/llvm-project/pull/90845 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
