[RISCV] Don't parse the decimal minimum value for fli.s/fli.d/fli.h.

There are a couple bugs in the current support for this:
-We do all the parsing in single precision so any value less than or
 equal to the minimum fp32 is accepted as the minimum value for f64.
-To support fp16 minimum value, getLoadFP32Imm has a special case, but
 that causes a miscompile in CodeGen.

Differential Revision: https://reviews.llvm.org/D145542

diff --git a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
index b2f7092..4a472e9 100644 (file)
--- a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -494,8 +494,12 @@ public:
   bool isLoadFPImm() const {
     if (isImm())
       return isUImm5();
-    return Kind == KindTy::FPImmediate &&
-           RISCVLoadFPImm::getLoadFP32Imm(APInt(32, getFPConst())) != -1;
+    if (Kind != KindTy::FPImmediate)
+      return false;
+    int Idx = RISCVLoadFPImm::getLoadFP32Imm(APInt(32, getFPConst()));
+    // Don't allow decimal version of the minimum value. It is a different value
+    // for each supported data type.
+    return Idx >= 0 && Idx != 1;
   }
 
   bool isImmXLenLI() const {

diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h
index ac7fe95..22b6a73 100644 (file)
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.h
@@ -398,11 +398,6 @@ inline static uint32_t getFPImm(unsigned Imm) {
 /// floating-point immediate value. If the value cannot be represented as a
 /// 5-bit binary encoding, then return -1.
 static inline int getLoadFP32Imm(const APInt &Imm) {
-  if ((Imm.extractBitsAsZExtValue(9, 23) == 0b001110001 &&
-       Imm.extractBitsAsZExtValue(23, 0) == 0) ||
-       Imm.extractBitsAsZExtValue(32, 0) == 0)
-    return 1;
-
   if (Imm.extractBitsAsZExtValue(20, 0) != 0)
     return -1;
 

diff --git a/llvm/test/CodeGen/RISCV/float-zfa.ll b/llvm/test/CodeGen/RISCV/float-zfa.ll
index 7700f57..ab85ad0 100644 (file)
--- a/llvm/test/CodeGen/RISCV/float-zfa.ll
+++ b/llvm/test/CodeGen/RISCV/float-zfa.ll
@@ -77,11 +77,12 @@ define float @loadfpimm9() {
   ret float 255.0
 }
 
-; FIXME: This is the f16 minimum value. It should not be supported for f32.
+; This is the f16 minimum value. Make sure we don't use fli.s.
 define float @loadfpimm10() {
 ; CHECK-LABEL: loadfpimm10:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    fli.s fa0, min
+; CHECK-NEXT:    lui a0, 231424
+; CHECK-NEXT:    fmv.w.x fa0, a0
 ; CHECK-NEXT:    ret
   ret float 0.00006103515625
 }

diff --git a/llvm/test/MC/RISCV/zfa-invalid.s b/llvm/test/MC/RISCV/zfa-invalid.s
index 0263d61..f565c96 100644 (file)
--- a/llvm/test/MC/RISCV/zfa-invalid.s
+++ b/llvm/test/MC/RISCV/zfa-invalid.s
@@ -46,3 +46,29 @@ fli.s ft1, -inf
 # CHECK-NO-RV64: error: invalid floating point immediate
 # CHECK-NO-RV32: error: invalid floating point immediate
 fli.s ft1, -nan
+
+# Don't accept decimal minimum.
+# CHECK-NO-RV64: error: operand must be a valid floating-point constant
+# CHECK-NO-RV32: error: operand must be a valid floating-point constant
+fli.s ft1, 1.1754943508222875079687365372222456778186655567720875215087517062784172594547271728515625e-38
+
+# Don't accept decimal minimum.
+# CHECK-NO-RV64: error: operand must be a valid floating-point constant
+# CHECK-NO-RV32: error: operand must be a valid floating-point constant
+fli.d ft1, 2.225073858507201383090232717332404064219215980462331830553327416887204434813918195854283159012511020564067339731035811005152434161553460108856012385377718821130777993532002330479610147442583636071921565046942503734208375250806650616658158948720491179968591639648500635908770118304874799780887753749949451580451605050915399856582470818645113537935804992115981085766051992433352114352390148795699609591288891602992641511063466313393663477586513029371762047325631781485664350872122828637642044846811407613911477062801689853244110024161447421618567166150540154285084716752901903161322778896729707373123334086988983175067838846926092773977972858659654941091369095406136467568702398678315290680984617210924625396728515625e-308
+
+# Don't accept decimal minimum.
+# CHECK-NO-RV64: error: operand must be a valid floating-point constant
+# CHECK-NO-RV32: error: operand must be a valid floating-point constant
+fli.h ft1, 6.103516e-05
+
+# Don't accept single precision minimum for double.
+# CHECK-NO-RV64: error: operand must be a valid floating-point constant
+# CHECK-NO-RV32: error: operand must be a valid floating-point constant
+fli.d ft1, 1.1754943508222875079687365372222456778186655567720875215087517062784172594547271728515625e-38
+
+# Don't accept single precision minimum for half.
+# CHECK-NO-RV64: error: operand must be a valid floating-point constant
+# CHECK-NO-RV32: error: operand must be a valid floating-point constant
+fli.h ft1, 1.1754943508222875079687365372222456778186655567720875215087517062784172594547271728515625e-38
+

diff --git a/llvm/test/MC/RISCV/zfa-valid.s b/llvm/test/MC/RISCV/zfa-valid.s
index 4324992..21d5d92 100644 (file)
--- a/llvm/test/MC/RISCV/zfa-valid.s
+++ b/llvm/test/MC/RISCV/zfa-valid.s
@@ -24,11 +24,6 @@ fli.s ft1, -1.000000e+00
 # CHECK-ASM-AND-OBJ: fli.s ft1, min
 # CHECK-ASM: encoding: [0xd3,0x80,0x10,0xf0]
 # CHECK-NO-EXT: error: instruction requires the following: 'Zfa' (Additional Floating-Point){{$}}
-fli.s ft1, 1.1754943508222875079687365372222456778186655567720875215087517062784172594547271728515625e-38
-
-# CHECK-ASM-AND-OBJ: fli.s ft1, min
-# CHECK-ASM: encoding: [0xd3,0x80,0x10,0xf0]
-# CHECK-NO-EXT: error: instruction requires the following: 'Zfa' (Additional Floating-Point){{$}}
 fli.s ft1, min
 
 # CHECK-ASM-AND-OBJ: fli.s ft1, 1.525879e-05
@@ -194,11 +189,6 @@ fli.d ft1, -1.000000e+00
 # CHECK-ASM-AND-OBJ: fli.d ft1, min
 # CHECK-ASM: encoding: [0xd3,0x80,0x10,0xf2]
 # CHECK-NO-EXT: error: instruction requires the following: 'Zfa' (Additional Floating-Point){{$}}
-fli.d ft1, 2.225073858507201383090232717332404064219215980462331830553327416887204434813918195854283159012511020564067339731035811005152434161553460108856012385377718821130777993532002330479610147442583636071921565046942503734208375250806650616658158948720491179968591639648500635908770118304874799780887753749949451580451605050915399856582470818645113537935804992115981085766051992433352114352390148795699609591288891602992641511063466313393663477586513029371762047325631781485664350872122828637642044846811407613911477062801689853244110024161447421618567166150540154285084716752901903161322778896729707373123334086988983175067838846926092773977972858659654941091369095406136467568702398678315290680984617210924625396728515625e-308
-
-# CHECK-ASM-AND-OBJ: fli.d ft1, min
-# CHECK-ASM: encoding: [0xd3,0x80,0x10,0xf2]
-# CHECK-NO-EXT: error: instruction requires the following: 'Zfa' (Additional Floating-Point){{$}}
 fli.d ft1, min
 
 # CHECK-ASM-AND-OBJ: fli.d ft1, 1.525879e-05
@@ -369,11 +359,6 @@ fli.h ft1, -1.000000e+00
 # CHECK-ASM-AND-OBJ: fli.h ft1, min
 # CHECK-ASM: encoding: [0xd3,0x80,0x10,0xf4]
 # CHECK-NO-EXT: error: instruction requires the following: 'Zfa' (Additional Floating-Point){{$}}
-fli.h ft1, 6.103516e-05
-
-# CHECK-ASM-AND-OBJ: fli.h ft1, min
-# CHECK-ASM: encoding: [0xd3,0x80,0x10,0xf4]
-# CHECK-NO-EXT: error: instruction requires the following: 'Zfa' (Additional Floating-Point){{$}}
 fli.h ft1, min
 
 # CHECK-ASM-AND-OBJ: fli.h ft1, 1.525879e-05