[llvm] 8ff1422 - [RISCV] Fix incorrect use of Zfa fli instruction for negative minimum value. (#70411)

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2023-10-26T22:11:58-07:00
New Revision: 8ff14223536d6645d7c92b4488e3eb676e548cb1

URL: https://github.com/llvm/llvm-project/commit/8ff14223536d6645d7c92b4488e3eb676e548cb1
DIFF: https://github.com/llvm/llvm-project/commit/8ff14223536d6645d7c92b4488e3eb676e548cb1.diff

LOG: [RISCV] Fix incorrect use of Zfa fli instruction for negative minimum value. (#70411)

isSmallestNormalized() only considers the magnitude, not the sign.

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.cpp
    llvm/test/CodeGen/RISCV/double-zfa.ll
    llvm/test/CodeGen/RISCV/float-zfa.ll
    llvm/test/CodeGen/RISCV/half-zfa-fli.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.cpp
index 7919189d198c8d1..ed8ae4a7a4550d4 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.cpp
@@ -251,7 +251,7 @@ int RISCVLoadFPImm::getLoadFPImm(APFloat FPImm) {
          "Unexpected semantics");
 
   // Handle the minimum normalized value which is 
diff erent for each type.
-  if (FPImm.isSmallestNormalized())
+  if (FPImm.isSmallestNormalized() && !FPImm.isNegative())
     return 1;
 
   // Convert to single precision to use its lookup table.

diff  --git a/llvm/test/CodeGen/RISCV/double-zfa.ll b/llvm/test/CodeGen/RISCV/double-zfa.ll
index 9f244f0daacf55d..162f33dd5ac9dd2 100644
--- a/llvm/test/CodeGen/RISCV/double-zfa.ll
+++ b/llvm/test/CodeGen/RISCV/double-zfa.ll
@@ -156,7 +156,8 @@ define double @loadfpimm17() {
 define double @loadfpimm18() {
 ; CHECK-LABEL: loadfpimm18:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    fli.d fa0, min
+; CHECK-NEXT:    lui a0, %hi(.LCPI16_0)
+; CHECK-NEXT:    fld fa0, %lo(.LCPI16_0)(a0)
 ; CHECK-NEXT:    ret
   ret double 0x8010000000000000
 }

diff  --git a/llvm/test/CodeGen/RISCV/float-zfa.ll b/llvm/test/CodeGen/RISCV/float-zfa.ll
index ec982a78dfe767e..6f9e5ec035224df 100644
--- a/llvm/test/CodeGen/RISCV/float-zfa.ll
+++ b/llvm/test/CodeGen/RISCV/float-zfa.ll
@@ -110,7 +110,8 @@ define float @loadfpimm12() {
 define float @loadfpimm13() {
 ; CHECK-LABEL: loadfpimm13:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    fli.s fa0, min
+; CHECK-NEXT:    lui a0, 526336
+; CHECK-NEXT:    fmv.w.x fa0, a0
 ; CHECK-NEXT:    ret
   ret float 0xb810000000000000
 }

diff  --git a/llvm/test/CodeGen/RISCV/half-zfa-fli.ll b/llvm/test/CodeGen/RISCV/half-zfa-fli.ll
index 73a77660eb3bdcb..577b774c27a0b36 100644
--- a/llvm/test/CodeGen/RISCV/half-zfa-fli.ll
+++ b/llvm/test/CodeGen/RISCV/half-zfa-fli.ll
@@ -216,7 +216,8 @@ define half @loadfpimm14() {
 define half @loadfpimm15() {
 ; CHECK-LABEL: loadfpimm15:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    fli.h fa0, min
+; CHECK-NEXT:    lui a0, %hi(.LCPI14_0)
+; CHECK-NEXT:    flh fa0, %lo(.LCPI14_0)(a0)
 ; CHECK-NEXT:    ret
 ;
 ; ZFHMIN-LABEL: loadfpimm15: